Mine are flat too. Adjustments, if needed, are made on the spot, but they typically need no adjustment.
I think if you're used to mixing already it helps, cuz you automatically know what to do to make it sound good in a live situation or in a band context, so you set it up like that, and when you plug in at the gig, it just sounds right, save for the odd trouble freq here and there, but that's always venue specific.