Your question is not very clear here. If you are asking whether a Flow frame classic (6 Flow frames) super can sit on top of a Langstroth medium box, the answer is yes. No adaptation needed, they just fit.
If you are asking whether you can put the plastic Flow frames into a medium Langstroth box, the answer is definitely no. The plastic frames are too deep to fit.
Thinking about this again, maybe I have missed something, so... Huh?? Errm, the Langstroth medium frames will fit in any Langstroth medium box. An 8-Frame Langstroth medium box (with Langstroth medium frames in it) will fit above or below any cedar boxes from Flow. If you need clarification, please ask again.