Non crossup timing for the s HP is when her fist is still extended. Earlier. If V Skill crosses up, the s HP combo timing is after Cammy has retracted her fist about 25% of the way. This can be a match losing or winning combo. s HP has way more range than c MP so it will almost always combo after V Skill hits, unlike c MP. But c MP is faster than s HP and is a frametrap if V Skill got blocked, which s HP isn't.