I will debate it. The ECU can matter. Points is an on off switch. Very little voltage drop across the points if the ground is good and the points are healthy. So the ballast is set to the coil based on that factor.

It is a little funny to think an electrical engineer wasn't involved with the ECU ballast selection. The ECU also act as a switch, but it is a transistor that has a diode properties, and diodes have voltage drop. Depending on the power switching transistor they used it can cause a voltage drop between .5 to 1.5 volts or more. Additionally, if can have a current limiting resistor built into the circuit. Finally, the dwell on points is a fixed value partially set by points gap. ECU has a dwell set electronically, and it could be made to vary based on rpm. I don't know if it is, but more advanced ECU can do that. The pulse from the distributor coil varies in amplitude based on RPM, and that can be measured.

Regardless, the maker of the ECU, knows your swapping into a MOPAR points set up, they know the manufacturer coil. So, I would use the recommended ballast.

How much does this all matter, probably not much as long as values are close.

In the end the coil is designed to provide more KV for discharge then a normal engine needs. It is over sized to account for deterioration of the ignition system (wires, battery, spark plugs) and poor fuel, fuel mixture and environmental.