Hi rstrats,
As I pointed out in one of my posts above, the wording may have been chosen to draw a memorable parallel with the LXX wording used in Jonah. And I could also see the possibility of the writer of Matthew choosing this wording just for its effects on the readers of his account.
I do understand that in the account of Jesus' death and resurrection there were not three actual days and nights involved. But the post-resurrection accounts in the gospels and Acts don't mention any of the disciples - or even the religious leaders who had him killed - quibbling over this discrepancy.
If all this happened in our time I don't doubt that these discrepancies would be highlighted ad nauseum. But my understanding is that people of the ANE were, generally, more concerned with the ideas conveyed rather than the actual precision of the wording.