User blog comment:B214/Question and Answers 6/@comment-213.106.131.123-20160525231323/@comment-134.39.58.33-20160526160204

Imagine Issei's base power = 4

Boosted Gear "BOOST" equation:   4^n

n = number of BOOST's used.

So, if Issei BOOSTs 3 times, it'll be   4^3 = 64