issues with update of info on multiple items in iTunes 12.1.2.27

Mac OS X 10.10.3 (just installed last week, although I had this same problem on iTunes 12.x on Mac OS X 10.8.5 as well).

Mac Pro 12-Core 3.33Ghz

16GB

2TB drive (multiple drives, actually)

I use iTunes to manage my library for Serato (first Serato Scratch Live, and now Serato DJ), so editing many song tags basically daily as I add / update my library.

I have 30,000+ songs in my library.

Prior to iTunes 12, I could select multiple songs in iTunes and modify the:

- comment (I need to delete the detail, as I used Mixed In Key to place a harmonic key tag in this location. Where there is data there, Mixed in Key can't always update the tag... So prior to key analysis I blank the field. But iTunes won't let me just blank the comments in multiple songs because the prior data for all items for this field don't currently match). I have to set them the same, then it will allow me to blank them.

- composer - same issue as above.

This functionality has worked on both of these fields every prior version of iTunes I've used since I got Serato- several years ago.

-BPM (unless all BPMs are the same #, you can't just delete an existing entry- it shows you deleted it in the Get Info box, but doesn't appear to clear it in the songs tags, so you have to set the BPM to all the same BPM to be able to clear them and it actually work (clearing them).

Basically a similar problem / behavior like the comments / composer....

This functionality also has worked on every prior version of iTunes I've used since I got Serato.

- click box for "Album is a compilation" shows similar behavior. If I imported multiple compilations, and I want to make sure the box is ticked, it won't let me uncheck then recheck it, so that all items will now be checked and updated to be compilations.

If there is so much as 1 file that is different than the rest, you can't change it and have to find which song is the offender.

This functionality has worked on every version prior of iTunes I've used since I got Serato.

If I have to open a case under my AppleCare so be it- but I don't think I should have to do that.

I would like a response from an Apple employee on this.... how Apple software engineers screwed up something that has always worked as long as I have had iTunes is beyond me...

Regards,

Ted