Creed Cuirass +2 is DT-10% x.x so that's 16% total.
I think MDT cap is still 87.5%ish still but if it is then I think that should hit 88%
Where are you getting 87.5% from out of curiosity, wiki hasnt always been known to be right but all Aegis' have a -mdt thats ontop of 50% mdt cap and the 95 version has -45% mdt so potentially 95% mdt. If this is the case then you still want at least around 15 mdt in gear and af3+2 cuirass ontop. You might take an aga spell with low emnity for example and the cuirass might perform worse than avalon.
BTW imo when it comes to the other gear mdb legs, askar feet and gauntlets when youve got 95% mdt, mdb is less relevant, prob best to keep af3 mostly for the haste partly for the absorb. But you could spell interrupt with a sword swing, and obviously kill the mob quicker, I know youll only swap into it Briefly but some mobs you might not be quite sure how fast it casts and swap into mdt too early. Even for a split second with 95% mdt, mdb is meh may as well keep af3+2 on im sure.