Different input rules for different characters?

[Neophos]

Alright, while fooling around in practice mode with V. Akiha, I found that 4, 236C activated her arcdrive. Seeing as I've played on keyboard for a while now, I wondered why I hadn't discovered this earlier.

However, when trying it with Nero, 4, 236C always gave his EX crows, and only 41236C activated the arcdrive. I'm sure my input was a close to identical as I could possibly make it, yet I got an arcdrive 95% of the time with V. Akiha using 4, 236C and never (unless I "messed up" and did 41236C instead) with Nero.

So, the question: Does different characters have different rules about input (varying priority on which specials come out?), or did I magically get awesome keyboard crushing skills whenever I picked V. Akiha?

EDIT: For added clarity, I added two replays. Turn on input display and watch them. The input is near identical, yet obviously different moves come out.

[Lolly]

I've heard of similar weirdness before in relation to Vakihas arc drive. A friend of mine playing on pad said he'd difficulty executing her AD for her, but only for her..there were no problems with anyone on KB tho and every other character was no problem on both.