grammar - になるほど in this sentence

I can not understand very well the meaning of "になるほど" in this sentence, from a Japanese Dragon Ball Guide Book.

(合体によるパワーアップは、)２人の戦闘力の合計ではなく、掛け算になるほどの凄まじさ！

Is it maybe something similar to the construction "The more... the more..."? Or does it have relations with "I see" なるほど?

And, in your opinion, can this translation be correct?

"The Power-Up of the fusion (context: by means of Potara earring), it's something impressive closer/more similar to multiplication rather than a sum of the power forces of the two warriors."

Answer

XほどY (or XくらいY) in this context means "Y to the point where X" or "so Y that X". The "the more ～, the more ～" construction is not relevant. This なるほど is not relevant, either. You have to add の if the following modified word is a noun. 凄まじい is an adjective, and 凄まじさ is its nominalized form ("-ness").

• 目で見えないほど小さい so small that it's invisible; too small to see


• 驚くほどの値段 the price so expensive/inexpensive that it's surprising; surprising price


• 問題になるほどの大きさ the size big enough to be problematic

So かけ算になるほどの凄まじさ is "intensiveness to the point where it becomes a multiplication" or "the tremendous power going up in a multiplicative manner (rather than the usual additive manner)". The sentence says the fused power increases in a way the fusion of 100 and 100 becomes 10000 rather than 200, for example.