I have not tried that, but I DON'T think it will supply much more juice. I might try that later. My logic is, I did not get more total output at 4x with a 55w bulb than with a 32w bulb. I have no reason to believe a 64w bulb(2x32w) will make a difference. To get more total juice from a single 4x ballast, I think it is better to do 2 2xOD, then each will get about 50watts, I think that's what lumpyfunk was asking earlier(I will measure later). I did do 2x measurement, 54w, but with the other two leads free. When the other leads support another bulb 2x, then the ballast factor drops slightly.
Flourite, wet/dry, AHSupply 302w PC, PinPoint controller
15w T6+15w T8
40w T6 ODNO4x, no CO2. Discus grow out.
10gallon Tonina tank, 2x15w T6 ODNO 4x
I will do aquascapes after I collect all the plant species and grow them to perfection.