Unfortunately, they may never post. Because of certain tax issues, when you give your FFP number, rental agencies pass along certain taxes to you. DL falls under the 50 cent per day surcharge, capped at $2.00.

But by not giving your DL number at the time of rental, this tax/surcharge was not added to your bill. Dollar may be unable to give you your miles because the tax was not paid.

I do see that the Dollar website includes an option for requesting miles when the number was not given at the time of rental, but I thought I had previously seen an error pop up when that option was selected that said Dollar would be unable to credit mileage in that case. I could be wrong, however.

If I am wrong, in my experience, you should expect to wait the full 6-8 weeks before receiving the mileage credit. Dollar's system is not automated and mileage transactions must be processed manually, so don't expect mileage to be credited quickly. If OGG is a franchise--and I believe it is--there may be further delays as corporate headquarters might request certain documentation from the location to be faxed or mailed if they cannot pull what they need out of the computer system and/or they arrange to bill the franchise for the mileage (the renting location pays the fees, in the neighborhood of $4 per transaction, associated with granting mileage).

In the future, if you do not have your FFP number when you are reserving the car or renting the car, call in and request it to be added before you return the car and the return greeter closes your rental contract with the handheld check-in device. Once the contract is closed, it becomes more difficult to add additional items like the FFP number and the associated taxes, and your request is more likely to get lost in the process.