Even if the equipment will operate successfully on 208V, when a manufacturer specs 220V, it's in your own best interest to give them what they ask for, if only for warranty's sake. It saves a World of negotiating when some part on their machine breaks, if only because they can't claim the old "Electrician Supplied the Wrong Voltage" line.
16/32 volt transformers can be used in a boost arrangement to get about 222 Volts. You can almost hear the manufacturer's smile when verifying with them if that's OK over the phone.
All too commonly, guys will use 12/24 volt transformers and boost the voltage up to about 239 from 208, thinking they've hit the "target". The target is 220.
Take away their excuse!