Configuring preferences and options in Outlook.com
That snapshot you posted only shows 1 storage. It's a glitch. The new policy should show 2 storage, Microsoft Storage (5 GB limit) and Mail Storage (15 GB limit). Outlook attachments total size now affects your lower 5 GB limit. Yeah I know it is confusing. Try signing out, clearing browser cache and signing back in. If you still don't see 2 sections in General - Storage option, wait a few more days.