ineedausername wrote:
... all the drops are terminated at the wall plates using a 75ohm 25db rl terminator ...
MoCA modulation is different than TV channels. It's designed to go forward and backward through splitters. You might want to try removing some or all of the terminators and see what that does.
If that fails, go back to trying to minimize the number of splits on the paths between the router and WiFi extenders. Remember that a 4-way splitter is really three 2-way splitters; each signal goes through two splits between input and output.
If all this doesn't help, you might want to look into pulling cable just for the connection between the router and the extenders.
Good Luck.