RXSF

Hi Folks,
I have a quick question for you guys regarding discount code I applied to a future rental. My original booking is from a Friday night to Monday night, and I randomly set a time for 8:30pm for pickup and return. I have the amex platinum contract price as well as the free emerald exec status. While doing my research, I did the obligatory retailmenot search for a promo code and indeed found a free weekend day code with a three day minimum rental. Code is NF44Z5JDL and a quick search references it back to BJ's travel site. Because this is an airport booking, it saved me $82 dollars!

Well now I actually booked my flight and I will arrive later than 8:30pm (around 10:00pm) and I will return the vehicle before my flight back at 6:00pm. I tried to log in and modify my booking, but then it says the discount code cant be applied anymore. I am guessing because I don't meet the three day minimum anymore?

My question is two part. The first is, will I get away with using the discount code on top of my amex contract price even though I have no affiliation with BJ's? And second, will something happen to my reservation (and discount upon returning) if I leave the time as is and pickup the vehicle later than reserved and return the vehicle early so that I don't meet the 3 day minimum?

Thanks in advance