it really doesn't need more charges imo, the Lex is just dumb broken at this point, with how strong it is I don't think it should even have 20 charges. And with the Bronco being basically a rocket launcher of sort, compared to like...the LATO incarnon, I think 20 shots is reasonable.
same with Latron and Strun tbh, I mean, the Paris Incarnon which is a VERY good and balanced Incarnon, only has 20 charges which have to be charged and fired, not even explosion... and then you got the Latron and Strun.