He's probaby right. That is the key. I could tell you what I think but instead I encourage you to look at the SV27 prop thread. I can't imagine a question that hasn't been answered there. Also the 4200 are in mah (mili-amp hours) a sort of discharge vs. time unit not pure amps. (we wish). Welcome aboard. Good to hear there are that many running together.
http://www.offshoreelectrics.com/prop_balance.htm