Is there any way to incorporate rolling rates?

It would be nice if you had the option to make an ad where the strike price is at the time of payment, or one that doesn’t automatically fund the transaction. I realize this doesn’t make sense in all cases but it does in the situation where someone wants whatever amount of XMR a fixed amount of cash will get them. Asking people to remake the transaction is a technically sufficient solution but not a very professional-feeling one. I can’t help but wonder if there are ways to avoid that in some instances.

Thanks for the suggestion!