Randy, I think I've lost the picture here. Your original post indicated that *adding* the EP600 reduced the output of the EP350s, but later posts seemed to imply that the issue was "just" a difference in gain/sensitivity/whatever between the 600 and the 350.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8