Opening the hive sets them back, because it's a disturbance, just like smoke. If they can afford to lose the honey you're going to rob, maybe don't use smoke at all, to avoid contaminating the honey. Just stick with an escape, or a brush and a suit. Bees *really* hate being brushed, FYI.
Just because they have excess now, which may be during your flow, doesn't mean that they won't need the honey to get through a dry spell in the late summer/early fall. Think forward before you rob. Is the taste worth having to feed a month early? Maybe, maybe not.