I'm thinking that those volt amps numbers are only good for the same brand and or similar model welder inverter's, for instance the newer Miller XMT 350 too the Miller 354-304 inverters, the volt amps are quite close, go to a different brand and they might be off.
I have a Miller 211 with (Auto Set) had for it 3 years now and last month I started trying that auto set feature, I'm kinda liking it, set one dial on .030 wire setting, set the other dial on how thick of steel that's being welded, like 1/4" and it automatically has the right wire speed and heat, setting goes from 24 ga.-3/8", just one dial to adjust.