FPA is calculated from Baro inputs. When showing 2200 (and it’s actually at 2000) it “thinks” it’s higher then it is. Ergo it needs a higher descent angle to compensate to the threshold where the correction is zero.
Remember the correction amount is relative to height over ground. The correction at 2000’ is twice that at 1000’ etc. Rather than the complex formula and apps, just use 4•ISAD•height over ground/1000.