PS: you could also optimize the 1 bar combo with:
jip, 34~noxious, f412~reptilian dash, njp, 21, f21 1+3 mb, f412~slide (44%)
But it is still a waste of a bar for not much additional damage.
In fact, in general, it's better not to use meter mid combos. Unless it is as an armored combo starter (ex-swipe) or to activate nimble after f412. Otherwise, it is really not worth damage-wise.
Reptille's meter is so hard to build that it is an extremely precious asset that you have to use wisely. I would keep it for things like armor, breakers, setups with ex slow forceballs, corner carry with ex-nimble combo, etc.. things that can really make a difference turning the momentum to our favor.
edit: also worth a bar to use it on b2 or f21 combos.