Best exp while duo bard/rog

[Donruss]

I have been reading about how experience works. I understand that my lvl21 rog may have less exp points than the lvl20 bard I group with. What lvl should the rog be vs. the bard for maximum exp?

He is also kinda the tank so things con high to him compared to me... Makes it kinda tough if our lvls get too far apart.

Or am I being stupid and we would get the best exp at the same lvl?