The point I have made is that if
the mass of atomic particles increases monotonically with cosmological time, then atomic clocks would 'speed up' "uniformly in the whole universe".
This would occur for example in a mass field theory such as Fred Hoyle's described in On the Origin of the Microwave background
The problem would be that we would not be able to notice this increase in clock rate unless there was another kind of clock to measure it against.
In SCC theory such a clock would have been provided by the photons in the microwave background.
The secular increase in atomic clock rates would then be observed as cosmological red shift, a thought pertinent to the OP question.