Transformers work both ways, it normally doesn't care if it is step up or step down. The only kicker is if it contains some internal diodes or capacitors or such as noise reduction devices. I wouldn't think it would unless it was for a sensitive location like hospitals, tv station, etc.  As far as 208 instead of 220, it shouldn't matter other than at a full load where it will draw a bit more current than at the higher voltage. The difference is less than 10%, and power at my shop/hangar has been known to fluctuate by that much.

Kevin Alderman

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