I have my delivery time set to 45mins. and the pick-up time set to 15mins.
I placed a test order at 1.31pm for a delivery and the delivery time after checkout showed 3.00pm which is 90 minutes.
For the pick-up order I did the order at 1.33pm and the pick-up time after checkout showed 2.00pm which is 27 min.
I have tried a few settings and none of them seem accurate.