The PFT course at TBS wasn't exactly "reasonably level ground." So, it could follow that the OCS course isn't exactly 3 miles.

When I went to ocs the avg was 18:30-19:30, I was at 18:30.
One thing about OCS PFT's: They are a ***** to run. You are constantly tripping over other candidates and trying to pass people on a dirt road. That's only when running with one company. Our final was with two companies...forget about it. They'll say rabbits should get up front, if you have any desire to run faster than 19:30, you'd better start in front.
I am guessing the only difference between running the PFT course wherever you and your OSO do it and running it at Quantico is the adrenile of that initial PFT is probably going to have you so pumped you will run your a** off.S/F
Wait a second...haven't you already been commissioned? Who are you to question the wisdom of someone who is applying for OCS?!?