I think the above assumes you want to store the decision to use calculated dates or not, so that you can make use of that decision going forward, as in be able to repeat the creation of data, or adjust it, according to the decision made. My apologies if that isn't the intent of the suggestion.
If that's what the suggestion is for but you don't want to make that decision permanent, then consider 2 option buttons in an option frame. Depending on which one is chosen, the method you use goes one way or the other. What you do after that I'm not sure. It seems that you will create data using one method or the other, but you don't say if the method (decision) chosen is to be saved or not.
At least the button idea might present a user friendly method of making that decision, which is what I thought you were after. Another tool you can use to "toggle" something is exactly that - a toggle button.
Last edited by Micron; 04-25-2018 at 09:51 PM.
Reason: clarification
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.