This worries me. There's no situation ever where you'll want to Doton and Raiton in any order, separated by a Kassatsu. Ever.
If there's a priority target in an aoe pull, you would be dropping Shadow Fang / Mutilate on it and single-target stuff to kill it. Ninjutsus would still be Katon/Doton.
If there's only one enemy, you should never be dropping Doton. Ever. Never ever ever. Under any circumstance. Ever.
If most enemies are about to die, leaving just one to Raiton after, you would Katon > Raiton, not Doton > Raiton.
I can't think of any other almost-right situation where Doton and Raiton would be mixed like this.
But yeah, as was said, every tick of Doton is automatically a crit if you Kassatsu into it.
