There's no reason I can think of not to spray it right before taking cuts. In fact, since one of it's benefits is that it is an anti-transpirant, it should be helpful to reduce water loss.
All I would say by way of caution is that as with all anti-transpirants, less is more- a very light mist that you allow to dry fully while still on the plant is better than spraying to ths point of runoff, which can suffocate parts of the leaves and give a place for rot to take hold.