my limited knowledge tells me your Railmaster is not performing to its COSC rating does 5 min/week = -42 sec/day???
I recently bought it pre-owned while I was on a trip out west, so I can only say what I was told. And that was that it has been serviced recently in the store - ED Marshall in Scottsdale. It is warranted for 1 year from the store. But if it runs that slow so soon after service, I'm not sure i trust them to do further service on it. Maybe Ill bring it to the Omega Boutique in NYC.
Make sure whoever does the work is equipped and trained to work on the co-axial escapement. Cheers, Al