My FPGA needs 2 amps?
It is very hard to estimate FPGA core power consumption when you haven't yet done the design (I've never done the FPGA design at the point I'm trying to spec the power supplies).

I don't know anything about recent Actel tools and parts, but X and A FPGA tools have power consumption estimation tools which you can play with.

Historically there have been horrible issues with some FPGA families needing huge currents at initialisation, so I tend to be very conservative with supplies for them, just in case.   If your design is really cost-sensitive, you should probably build a dev/prototype with a beefy power supply and suitable link where you can measure the actual current, then go for something smaller later.

Your post confuses me somewhat about which supplies you need to provide - there are usually at least three - I/O (sometimes several different bank voltages), core (low voltage, potentially lots of current) and PLL (usually core voltage, low current, should be quiet).