Inconsistent ability to modify Outline Level of custom Headings

I gave this a try, and now remember why I'm not using the approach you suggested -- in fact, I did try this at the start (it's all coming back to me now), but couldn't get it to work in the way I needed.  Basically, I'm using Word's "Write a Journal Template", except that I'm using the Title style for my chapter Headings, Heading 1 for my top subheading, and so on (it looks great).  I really like this template's Heading style, so I wanted to use those, rather than create ones from scratch.  So (and you can try this yourself), I created a document, and had subsequent lines of text formatted in each successive Heading style, i.e.:

Title

built-in Heading 1

built-in Heading 2

built-in Heading 3

built-in Heading 4

My goal was to take the style for Title and apply it to built-in Heading 1, the style for built-in Heading 1 and apply it to built-in Heading 2, i.e.:

style of (Title) ==> built-in Heading 1

style of (built-in Heading 1) ==> built-in Heading 2

style of (built-in Heading 2) ==> built-in Heading 3

style of (built-in Heading 3) ==> built-in Heading 4

style of (built-in Heading 4) ==> built-in Heading 5

In so doing, the Title style would now be Level 1, built-in Heading 1's style would be Level 2, etc.

To start, I tried applying (hereafter anytime I write "Heading #" I mean "built-in Heading #"):

style of (Heading 4) ==> Heading 5.   I did this by selecting the text that was formatted in Heading 4 style, and then (in the Styles Pane) clicked on the reverse triangle next to Heading 5 and selected "Update to Match Selection."  That did indeed change Heading 5's style to that of the original Heading 4.  

But when I tried to go up by one level, I ran into a problem.  When I tried applying: 

style of (Heading 3) ==> Heading 4, not only did Heading 4 acquire Heading 3's style, but Heading 5 did as well (not only in the Style Pane, but in the text)!  It was then impossible to fix this by going back to Heading 5 and re-applying the Heading 4 style, because that style was now gone: both the Heading 4 selection in the Style Pane, and the text to which I'd applied the Heading 4 style, were now Heading 3 style!  I.e., they're somehow linked together in a way that prevents this remapping.   I also tried it in the reverse direction, starting with Title, and ran into the same problem when I tried applying the style of Heading 1 to Heading 2.

Finally, I also tried the following, which didn't work either (I encountered the same problems described above):

style of (Title) ==> built-in Heading 1

style of (custom Heading 1) ==> built-in Heading 2

style of (custom Heading 2) ==> built-in Heading 3

style of (custom Heading 3) ==> built-in Heading 4

style of (custom Heading 4) ==> built-in Heading 5

So if you have a solution to this, that would be great. All of these Heading styles are quite complex (especially the Title's), so it's not practical to try to laboriously reproduce them using the Modify Style pane.  That's why I chose to create custom Headings.  These I could modify to match the style of an existing Heading with just one click (i.e., "Update to Match Selection").

Don't mess around with the Heading Styles.

Rather, in the Table of Contents Options dialog, assign the Title, Heading 1, Heading 2, Heading 3, etc styles to the desired TOC level (and, if necessay to achieve the desired layout, modify the formatting of the TOC # styles.)  

Note however, you can assign multiple styles to the same TOC level if desired.  For example, you could have both the Title style and the Heading 1 style assigned to TOC level 1 if that gives the layout that you require.

Rather, in the Table of Contents Options dialog, assign the Title, Heading 1, Heading 2, Heading 3, etc styles to the desired TOC level (and, if necessay to achieve the desired layout, modify the formatting of the TOC # styles.)  

Note however, you can assign multiple styles to the same TOC level if desired.  For example, you could have both the Title style and the Heading 1 style assigned to TOC level 1 if that gives the layout that you require.

Alas, modifying the TOC levels isn't sufficient for my purposes.  Indeed, a few weeks ago, after my initial attempt to remap the appearance of the built-in Headings failed, I did adjust the TOC levels.  The problem is this works great for the TOC, but leaves me without a Document Map that is properly indented (because the Document Map follows the Outline Level, rather than the TOC Level).  Without the proper indentations, the Document Map is hard to navigate.  I thus had to accomplish this by creating custom Headings, identical in appearance to the built-in Headings, but whose Outline Levels I could adjust.  Now my Document Map corresponds to my TOC.  But, the link to Shauna Kelly's page explains.

I'm using Word for Mac 15.31 with MacOS Sierra 10.12.3.

I'm using Word's "Write a Journal Template", except that I'm using the Title style for my chapter (Level 1) Headings, Heading 1's appearance for my Level 2 Heading, and so on (it looks great).  I really like the styles of the Headings in this template, so I wanted to use those, rather than create ones from scratch.  I accomplished this by creating custom Headings whose appearance is based on the style of the built-in Headings.  I.e., Here's what I have.

[Note: "OL" = Outline Level; and I'm using "style" to mean all parts of the Heading's style except for the OL.]

OL1:  Title, OL set to 1

OL2: custom Heading whose style is that of built-in Heading 1

OL3: custom Heading whose style is that of built-in Heading 2

OL4: custom Heading whose style is that of built-in Heading 3

OL5: custom Heading whose style is that of built-in Heading 4

In this way, both my TOC Heading Levels, and the Heading Levels in the Document Map (in the Navigation Pane) match. However, I've been advised that, for various reasons, it's superior to have your document's structure be based on the built-in Headings rather than custom Headings (see http://www.shaunakelly.com/word/numbering/usebuiltinheadingstyles.html). This leaves me with just two options:

1. Change the OL's of the built-in Headings.
2. Change the style of the built-in Headings (so that, e.g., Heading 1 now looks like my chapter Title, Heading 2 now looks like Heading 1, etc.).

However, I've  been further advised not to change the OL's of the built-in Headings (that this could lead to unstable behavior).    Thus, if I want my document's structure to be based on built-in Headings rather than custom Headings, that leaves me with only option #2.  I tried doing that, but couldn't get it to work.  I.e., I tried doing this:

OL1: style of (Title) ==> built-in Heading 1

OL2: style of (built-in Heading 1) ==> built-in Heading 2

OL3: style of (built-in Heading 2) ==> built-in Heading 3

OL4: style of (built-in Heading 3) ==> built-in Heading 4

OL5: style of (built-in Heading 4) ==> built-in Heading 5

In so doing, the Title's style would now be at OL1, built-in Heading 1's style would be at OL2, etc.

To start, I tried applying (hereafter anytime I write "Heading #" I mean "built-in Heading #"):

style of (Heading 4) ==> Heading 5.   I did this by selecting the text that was formatted in Heading 4 style, and then (in the Styles Pane) clicked on the reverse triangle next to Heading 5 and selected

That did indeed change Heading 5's style to that of the original Heading 4.  

But when I tried to go up by one level, I ran into a problem.  When I tried applying: 

style of (Heading 3) ==> Heading 4, not only did Heading 4 acquire Heading 3's style, but Heading 5 did as well (not only in the Style Pane, but in the text)!  It was then impossible to fix this by going back to Heading 5 and re-applying the Heading 4 style, because that style was now gone: both the Heading 4 selection in the Style Pane, and the text to which I'd applied the Heading 4 style, were now Heading 3 style!  I.e., they're somehow linked together in a way that prevents this remapping.   I also tried it in the reverse direction, starting with Title, and ran into the same problem when I tried applying the style of Heading 1 to Heading 2.

Finally, I also tried the following, which didn't work either (I encountered the same problems described above):

style of (Title) ==> built-in Heading 1

style of (custom Heading 1) ==> built-in Heading 2

style of (custom Heading 2) ==> built-in Heading 3

style of (custom Heading 3) ==> built-in Heading 4

style of (custom Heading 4) ==> built-in Heading 5

So if you have a solution to this, that would be great. All of these Heading styles are quite complex (especially the Title's), so it's not practical to try to laboriously reproduce them using the Modify Style pane.  That's why I chose to create custom Headings.  These I could modify to match the style of an existing Heading with just one click (i.e., "Update to Match Selection").

I know some of you will want to suggest that I instead just modify the TOC levels, but this isn't sufficient for my purposes.  Indeed, a few weeks ago, after my initial attempt to remap the appearance of the built-in Headings failed, I did adjust the TOC levels.  The problem is this works great for the TOC, but leaves me without a Document Map that is properly indented (because the Document Map follows the Outline Level, rather than the TOC Level).  Without the proper indentations, the Document Map is hard to navigate.  I thus had to accomplish this by creating custom Headings, identical in appearance to the built-in Headings, but whose Outline Levels I could adjust.  Now my Document Map corresponds to my TOC.  But, for the reasons given in the above link, it would be better if I could do this with the built-in Headings rather than custom Headings.