Okay, AP first. MHXA has full control of Infinite Bean Paste now. It is said that she can turn half of the universe to dust and possesses infinite power. But we all know we're going iffy so, I think far higher is better option.
MHXA's AP should be:
7-A. 6-C with Cross-Calibur. Far higher with Infinite Bean Paste
For speed, it's MHX. New XEX Galactic Meteor Sword's Attack Speed should be Massively FTL+. It cut through temple body of Astaret after all. Ya know, the giant Rin in NP animation. It was pretty clear during Astaret Origin fight that it dwarfs countless stars, and XEX's power easily reached other side of it's body in seconds. Not to mention she's aiming that from Ishtar's spaceship which is very far away, interstellar level.
This shouldn't outlier or anything, it's an upgrade, that's like saying Gear 4 Luffy's Low 6-B is outlier because it's higher to his usual strength. This was never reacted against either so the scaling to other people argument is moot either, this scales only her.
MHX's Speed should be:
Massively Hypersonic (Has A+ Rank Agility, the highest rating possible for a Servant). Massively FTL+ Attack Speed with XEX Galactic Meteor Sword (Her sword managed to cut through temple body of Astaret Origin, which is big enough to dwarf countless stars, reaching other side almost instantly)
Riding: EX Talent for riding. She can’t manage most mounts and vehicles, but she is amazingly effective when it comes to piloting junk spaceships. To the point that she can make a ship with no warp function warp.