Here is what I have got per the treasury regulation I cited @Carl :
The requirements of ownership and use for periods aggregating 2 years or more may be satisfied by establishing ownership and use for 24 full months or for 730 days (365 × 2).
Note that this Reg states nothing about the "1st to the 16th" or leap years. In fact, it states "24 full months" OR "730 days". If you have a cite to support your proposition, then go ahead and post it here.
