I agree. You would expect to lose around 4% of your power between the pedals/crank and rear hub i.e. drivetrain efficiency is typically around 96%. So you could expect to lose about 8W @ 200W. This is what I typcially see between my crank PM and trainer power.
But 10-20W sounds a bit on the high side, especially if you see that sort of loss at relatively low power. I don’t know what PM is being used here, but I would tend to trust the Neo 2 readings. That’s got to be better than trying to work out the difference between 2 different bike PMs.