So those would fry the ATmega328?
No, the amount of current drawn from whatever source is determined by the device drawing the current, a arduino in this case. The fact that a voltage source has more current avalible then the load requires does not 'force' a higher current into the device. It's ohms law where the resistance of the load determines how much current will be drawn from a given voltage.
Your 120vac AC outlet on the wall can power a vacuum cleaner or a night light, and they both don't draw the same current from the outlet, right?