Albums sorted by <Album Rating> are actually sorted by a numerical value (an integer from 0 to 100) rather than the stars shown. So if two albums appear next to each other and they both have a rating of four stars, the better will album will take precedence according to sorting.
2. Although <Album Rating> is not on the list of tags available when creating a Virtual Tag, you can still type it in. Create a Virtual Tag (Preferences > Tags (1) > Define New Tags...) with only <Album Rating>
and show it in a column - you'll now see the numeric value you asked for. However, this is right now sorted as a string rather than a number (1, 100, 2, 20, ...) but we can fix that
Go to Preferences > Layout (1) > Configure Fields, look up your Virtual Tag and change type for your Virtual Tag to Number. (Note how you can select Rating here if you rather want to see stars.)
(If you would have used a custom tag, you would need to copy all your album ratings values into that custom tag for each track.)Edit:
Just realized right now that you said that the sorting works fine, so no need for me to point that out like I did above, sorry