Question about phosphorous in foods - Dr. Lisa??

Angel recently had a bad allergic skin reaction, probably to a new antibiotic that she was on. But since Fancy Feast had recently changed their can design, which often means that the formula has also changed, I decided to check whether the ingredients listed were different than the old cans. Angel's favorite flavors are the Tender Beef Feast and the Gourmet Chicken Feast. I noticed that both of these formulas changed from using tricalcium phosphate to dicalcium phosphate. Do you know why the manufacturer would have made this change, and whether it could affect the phosphorous available from these foods? In comparing ingredients, I notice that most premium brands of cat food tend to use tricalcium phosphate. I already use a binder to reduce Angel's phosphate intake, as she's in CRF.

Incidentally for Fancy Feast users, the other major change I noted on the labels was from "natural and artificial flavors" to "artificial and natural flavors," and the gourmet chicken feast variety now has "added color" listed, whereas it didn't before.