yes, i believe you just add them up. the only thing i'm not sure about is the T5 ballast, most ballast draw more amps to fire the bulb and then revert to a lower draw to sustain the light.

i bought me one of these to test my stuff out - http://www.energyfederation.org/cons.../cPath/388_254

only downside is it has a max draw of 15 amps...so it may not help in your case?