Hi Doug, thanks for the response!
I'd heard of calculation modes but hadn't messed around with those yet. I read the linked article and tested some of the settings on my repeat and various fields, but none of those seemed to help. I think you're right in that the empty repeat records are generated, but the calculations don't fire until the repeat becomes active and is loaded.
The defaults thing is essentially what I'm doing. There is a checkbox field outside the repeat and when selected it fills in some default answers within each repeat. Although the user still has to page through each repeat, the fact that they no longer have to fill in answers to for each repeat record is a big improvement, which I'm happy with. Was just hoping I could take it one step further.
Thanks for the suggestions!