Hey @Cin10 

I would suggest you use flow filters to stop profiles from entering in multiple flows at the same time.

One common practice we use if the purpose of the flows is similar is to add flow filter in the flow that has lower priority - for instance flow A is high priority, and flow B is low priority. So the flow filter should be in flow B - received email zero times» from Flow A» in the last X days (where X is the biggest time delay you have in flow A plus 1 day)

Also for the discount codes, always have one set of discount codes per flow, so basically both flows should have different discount code (even if the discount amount is the same)

let me know if this helps

Cheers

Arpit