I agree with pp- at 14 weeks you should be able to drop your MOTN. If you want to make sure you don't loose any supply, I would suggest doing it slowly. So increase your night stretch by half hour every day or every other day, until you reach the desired number of hours you want to sleep at night...speaking from my own experience (but I'm an HVP) I was at 6 pumps already when i reached my 12 week mark, and I always went a 5 hour stretch at night right from the start, I really did not handle the luck of sleep well. But I did have to get up at like 5 am to pump for a long time, just because I physically could not go longer then that with all that milk in my bb's. And from what I understand that is still considered a MOTN. I'm only able to sleep till 8 am now, that I pump 3 times a day and my supply is down quite a bit.
At 14 weeks your supply should be fairly established so if you drop the MOTN pump, you should be okay.
I dropped my MOTNP sometime between 10 and 12 weeks (a blur) and I didn't lose any ounces.