Post-Hebbian Learning

The specific Hebbian learning rule says that the weights change by a constant amount
Post-Hebbian learning rules can base the change on other things
Both post-Hebbian and anti-Hebbian learning rules are Hebbian in the broad sense.
Post-Hebbian rules eliminate the axonal weight problem
If the amount of the change is based on the existing weight,
higher existing weights change less, and lower existing weights more
The strengthening and weaking are offset, and the weights will tend toward an intermediate value
There will be a few large strengthenings, and many small weakenings
Similarly, inhibitory weights will also tend toward an intermediate value
This is all argument; can an experiment show this?