That UPS is twist lock for a reason - I believe the lowest draw a 110 twist lock will have is 20 amps. IIRC, APC's biggest 5-15P plug UPS used to be a 1000 or 1200.

I have a UPS (2200VA) that came with both a straight 15A plug and a non locking 20A plug. We're currently using the 15, but are moving offices. My new computer room has 2 30A twist lock outlets ...