I moved my iTunes library but it still updates files in the old location.

I have a 2008 Mac Pro on El Capitan. I had my entire iTunes library on an external drive (we'll call it Drive A). I quit iTunes, copied the entire folder to a larger drive (Drive B), then launched iTunes and went to Advanced in the prefs and pointed to the new media folder on Drive B. Downloading songs, updating apps, purchasing movies, etc. all saves the files into the correct structure on Drive B. BUT, it updates the "iTunes Library.itl" and "ITunes Library.xml" files back on Drive A. Even though the Advanced section of the prefs shows that the library is located on Drive B, it still updates the itl and xml file back on Drive A. I've looked through various Preference files to find what could be pointing to the old location in the hopes of manually editing it to point to the new location but I can't find anything. Anybody know how I can get iTunes to update the itl and xml file on the correct drive?