I think it may also depend on the bank you plan to use. I just had a similar case in that the seller was flipping and one bank (Chase) required he hold the property for 180 days, another (yup, Chase again) said 90 days from the recording date. Confusing, I know.
Your best bet is to speak to a lender directly. Call Matt Bukovy 773-416-7107 with Wintrust Mortgage or your local banker.