The plasma is just an alternative weapon for one of the attacks, but it's 6 attacks on the charge... right? 2 base, doubled for Paired, +1 for paired(second weapon), +1 for charging... right? the doubling from paired only triggers on the charge too. That's another reason I'm happy to learn about the stoping short strat.
Yes, your numbers are right. 2x2+1+1=6.