ITunes :: Sorting Album By Artist / Year

I've been having problems sorting _some_ albums. I'll give you a specific example: I rip Simon and Garfunkel's 'The Concert in Central Park' which has 19 tracks. I want them to play in continuous mode, and in order. I show track number in the columns, make sure all the tracks are of the same album and artist and I don't specify and sort options. Now I click on the column header 'Album by Artist/Year' and I see that track 16 is first followed by 18, 19 then 1,2,3, etc.

I'm not sure why 16,18 and 19 are out of order, but they are and I don't know what other field it is using to apply this sort order since I've turned off the sort fields. I should say that I think the sort fields are turned off since I selected all tracks, hit command-I and made sure that the artist and album are the same, then went over to the sorting tab and selected each checkbox and made sure that the field was blank. Clicked on OK, then went into each track one at a time and verified that the general info and sort info were as I specified.

If I change the sort column to be just 'Album' then it sorts correctly - I think that the year is messed up, so I add the year column to the display and see that it is 1982. I click on the year and the sort is just fine. I set it back to 'Album by Artist/Year' and the same bizzare sort shows up. The same mis-sort shows with 'Album by Artist' so I do a check on the artist name (even looking for leading or trailing spaces - nothing). I could probably delete the album and re-rip it, but I would rather find out why the sort is messed up so I can correct this problem.

Info:
MacBook Pro, Mac OS X (10.7.3)