I have added in some logic to detect when disc numbers skipped
That doesn't appear to be working.
Even with Disc# removed from gouping, I have an album tagged showing that it is Disc#1 of 2, disc # 2 is not in library, 'Album Complete?' still reports Y for complete album.
I also was looking for this option:
it would be disabled if Disc# was not used in Grouping, but would become selectable if used
It would basically allow for 2 groupings
1 for display of multi-disc albums as separate discs
1 for calculating the total track count of multi-disc albums as complete sets