Take Tenchi Nage for example; you can take a sitfall, forward roll, or backward roll off this technique in Aikido. I still have to fall but I have a choice of what kind of fall I take. You have the choice between the three.
Ahhh ... then we're just talking about differences (or perceptions) in training. In my experience, the only options I have are the ones presented to me by nage (not the technique). In the case of tenchi-nage, for example -- as it is practiced in my dojo -- done well, there is only one option (even if I "choose" otherwise).
Thanks for the clarification.