I think this is the right approach, I would leave the standard frames in until they start filling the Flow frames. I think once the Flow frames have been filled once the problem will go away.
Can I ask if you’ve waxed the Flow frames? Have they closed the gaps yet? Or are they staying completely away from them?
Shameless plug of link folllows for waxing the Flow frames:
http://forum.honeyflow.com/t/how-to-encourage-bees-to-use-the-flow-frames/5099/94?u=rbk