pH Controllors and CO2

I use a Sera Precision pH Controller as a solenoid in my CO2 dosing path.

I set my minimal pH level at 6.5. I regularily check and calibrate my controller and haven't found it to be out by a pH of .1 which seems fine by me.

CO2 is shut off at night.
dKH is around 4-5.

My question is this:

If I am using this method for controlling the pH, shouldn't I theoretically be able to crank up my CO2 to insane levels, and my system will really only dose CO2 as the plants need it?

I would think the main limiting factor would be how much CO2 I'm willing to waste.