'Nother random platy question.

I know a lower temp makes the female's gestation period longer. I'm horrible at remembering time but I'm pretty sure I've had my trio of platys for at least 2 months. I do remember the larger female looked already gravid when I bought her (I remember the
LFS guy commented on it)...and neither of the females have dropped yet although they both look insanely fat.

I had set my temp to mid-70s but between a frigid bedroom and poor circulation in the tank the temp has been down to 71-72 for a while. (I just got around to turning the heater up again although they all seemed perfectly happy.) Sooo I'm wondering how much that temp would slow down their gestation, or if there must be some other factor causing them to put it off so long.
EDIT: I found my post when I got them and it was October 26. So that's like what, a month and a half I think. So the large female anyway is a couple weeks overdue, the small female idk when exactly she got preggo so she might be on time.