According to Benchmark the amp in bridged mono the maximum unclipped output voltage is 45.5 Vrms (64.4V peak) into a 4 Ohm load.

I would expect it to be higher. If the rails are 60 volts then the peak volts should approach 120, say 100 Volts with losses, but the current won't support that as 25 amps are needed. BTW 18 amps is not an impressive amount of current for modern amp of that size. Should be more like 40 amps. The Mitsubishi Docking Amp of 1978 delivered 60 amps, I measured it!

Something is a little off here and the more I here the more I wouldnt want to bridge this amplifier. I have nothing against bridging in general and have made bridged amps.

The reason we bridge amplifiers is when WE DO NOT have a low impedance load. We bridge to get voltage not current. We bridge to get some juice into 8 ohms. When we have 4 ohms we dont bridge.

Where are the italics around here? All caps is my best substitute. :)