As in, only deny an Extra Turn if the Frozen troop gained mana from the specified 4-match? I think that’d muddy the mechanics up way too much. Imagine a case where an unfrozen troop sits in front of a Frozen one of the same color. Would you say that a 5-match that spills a single point of mana over into the Frozen troop would be enough to deny the ET? What if you matched a 5-match and a 3-match in that turn, does the 5-match go to the first troop and the 3-match to the second (thus ET) or vice versa (thus no ET)?
I get where you’re coming from, and in simple cases it makes sense that a troop untouched by collected mana would not impact the ET eligibility, but I think in practice it opens up too many edge cases to be practical.