For precrowns and postcrowns, the gifts are decided at the exact point of the prayer, not sooner.
If you can be pre/postcrowned, the gift will be determined just after the deity says "Mortal you should be rewarded for your perseverance."
It doesn't matter if you're at "favors greatly" or extremely/absolutely close (pre/post crown), or even just very close but with sufficient piety.
I am absolutely certain about that. In fact I can prove that.