I've found lots of bolts in place of fuses in old truck fuse panels, but if the motor says 2.5a I'd wanna go over the whole thing to find out why it'll blow a 10a .... could be a bad motor [even new] or a wire with melted insulation too close to a ground that's
not quite shorting .... if it ain't right fix it

the "AC 20a" will likely be to allow for the compressor, otherwise 10a is what the engineers thought it should never exceed - actually more like 6-8 with a fudge factor
Bill