Has anyone done a rental in Stamford and dropped off in Manhattan lately?

We're driving to Boston for the weekend. We're going to take Metro North to Stamford for a Thursday evening pick up, and returning on Sunday. The Stamford Avis closes at 4pm Sunday, which is not ideal, as I'm not sure what the after-hours situation is.

For pick-up/drop-off in Stamford, the car I want is ~$200. Setting a pick-up in Stamford and drop-off at the West 54th Street location skyrockets the price to ~$800. Is this right?