if the master is set to a max of 75 the slave will not go over 75
ie. when the master is 75 the slave is 25 and when the master is 25 the slave is 75.
I'm pretty sure that is incorrect.
I'm having the same questions as Dave in the OP, testing a new MP10 in my tank (total of 2). The "Anti-Syn" profile I use for the new 1ns pump uses Control Type "Anti-Synch", with the Maximum Intensity # set to 100. The Master Pump Number is "Vortech_1" - my first pump.
My Vortech_1 pump is currently running the Night profile, which has a Maximum Intensity of 30. My Vortech_2 pump has a single state in its outlet - Set Anti-Syn.
And that 2nd pump is BLASTING. Way, way more than 30%. Likely 100%.
It appears that Maximum Intensity setting in a profile using the "Anti-Synch" Control Type does indeed set the Maximum Intensity of the pump using the profile. Even as a slave.
It appears that to have an anti-synched slave have the same Maximum Intensity as the master, then you need to call a special profile for the slave - using the Anti-Synch Control Type - with the same Maximum Intensity as the intensity set in whatever profile the master is using.
If someone can speak authoritatively to the contrary, please do. But my testing definitely supports what I've stated above.