Looking at the voltage of the AS port trigger PD as seen by the shutter controller, we have just under 2V at 50W input. The maximum threshold is 2V, so this won't work. The QPD chassis of AS_C has serial number S1301506 indicating an R23 of 26.7K in the sum output. This needs to be reduced to 12.4K, or we have to reduce the modulation depth of the 45MHz before we reach 50W.