I've not used the SCF product before, but it looks like it should be OK, according to the specs. It may even be OEM on other makes that use Selespeed-type units.
So, working on the assumption that it is OK, and that you have no leaks, I would definitely suggest getting it hooked up to a suitable computer and checking for any transient codes.
There may well not be any, but if there are, it's a good starting point.
Re-check the grade of oil that went in the gearbox with the grade in the manual.
Otherwise, the next suspect is the clutch, but at mileage this low, it would have to be a problem with driving technique (NOTE: this is not a criticism of anyone's ability to drive) - the manual gives good instructions on how to drive a Dualogic, but pretty sure a lot of owners have never read it.