Assign test set folder to max one cycle

Please explain the logic behind the restriction that we are only able to assign a test set folder to max one cycle. Lets say I have a small set of regression test cases, would I not be interested in assigning it to every cycle? Or, I might be interested in re-running all test sets for the last cycle.

What in your opinion is best practice? Do I actually need to make as many copies of a test set, as I will use it in different cycles? Seems like redundance.

BW Peter Hansen