I’ve got quite a few combos with paul but I never ever use the shredder for AA because i find it so unreliable, what other AA can I use?
cr.HP… but it is not always usable.
st.MP works more often for me but still not everytime 
Paul has no reliable AA…
c.hp cancled into mp morta.
otherwise cl.mp and c.mp (against some).
your best anti air is jump lk tho.
cr.Fierce: You must input the move the moment you see them jump at you due to the slow start-up frames (is like 6 or 8), preferably when they are jumping a bit more directly over your head.
cr.Strong: The normal works when they are not so much above you, but more jumping towards you. Standing strong behaves similarly. I would be careful on which one to use on jumping attacks that lower the hitbox (Cody, Sakura, Yoshi, etc).
St.Forward: Think of it as a weaker version of Guile’s standing forward. Good for hitting neutral jumping and jumping from a far range.
Standing close fierce: Sometimes they move cleanly beats out cross ups, and slow safe jumps.
Ex slasher: Never use the non-ex versions they are ass. Do not rely on the auto correction of this move because it is terrible. It has some uses in a similar way as cr.fierce, in the sense it only hits on jumps near your head. I think of it like Sean’s dp in 3S. Oh, and never wake-up with this.
I’m basing this off the pre-patch, i still haven’t got internet at my new place so i haven’t had a chance to download the dlc characters or update the game.
OSU!