Just shot a few quick shots from a single 10-shot mag to check out the velocity of .22 cal CPL 14.3 gr pellets at various power settings, 200 BAR fill:
Lowest -- 385 fps
1/4 -- 660 fps
1/2 -- 830 fps
3/4 -- 930 fps
Full -- 960 fps
That is a spread of 4.7 FPE to 29.3 FPE. 615 fps would be 12.0 FPE, so it seems 1/4 power is probably just fine for shooting paper targets with the AA S410 ERB at a little over 12 FPE.
Also I did answer a question I was wondering. The power setting is independent of the cocking motion. That is, if you cock the action and then turn the power setting up, it shoots at the higher power, not at the setting at which the action was cocked, and vice versa -- if cocked at full power and then the power setting is turned down, it shoots a low power.