A Dicey Question on Advancement

A B4 Sorcery tests against an Ob 3 spell. Dice are rolled and 3 successes two of which are 6’s granting two more dice (now a total of 4 successes).
Do I count this as difficult test vs. a B4 Sorcery or as a routine test vs. a B6 Sorcery as there were two dice added from the open ended roll? (at which point the test wouldn’t really count anyway)
I can’t seem to find it in the rules, and the two things I can find that are related seem to cancel each other out.
(Help, FoRKs, and Advantages add to the dice vs. Advancement. Using a Fate point for Luck turns any roll into an open ended roll and does not add to the dice vs. Advancement.)
I realize that Artha is always a special case, but I remain uncertain on how to rule on this with open ended, non-artha dice.

I know I wouldn’t count the rerolled 6s, but I also could not find a rule in the book. So, I went hunting…Luke lays it down here.

So the answer is no. Rerolled 6’s (exploding dice) do not count against the number of dice rolled for advancement. That’s what I thought it would be but its always nice to get an official answer.
…Thanks Guys…