Update, I refreshed my surface today without the type cover attached and installed all the updates. Battery drain is still 1-2% per hour with display error popping up. I haven't run any other power or battery test yet because I only refreshed today. In a few days I'll run the tests to see if I notice any differences.
Scottfaber, I did take a look at the display error. Prior to the refresh, the display error would pop up frequently in almost exactly 15min intervals as you stated. After the refresh, it's popping up every 30mins or so. No idea what's going on here.
v0lum3, I did adjust this setting prior to the refresh and I didn't notice any difference. I'll try it again and update with any changes in a few days.