i think once you do one cycle, you get more back on the second cycle because you've hit the safety net. If you have already hit the safety net this year, you'll get a little bit more back but it really isn't a whole lot in the grand scheme of how much IVF costs. Maybe only $1000 difference?
If you only have one shot at the IVF i'd be doing it when you are emotionally ready. When you say one cycle do you mean one stim cycle plus any frozen embryo's you might get?