More information if needed:
Thrust scaling isn't linear, it gains faster at the start. Thrust inheriting takes the total thrust of that entity and adds it up to the main ship. This way you can bypass the diminishing thrust gains by splitting it up in multiple entities.
Solution would be to add the amount of thrust blocks to the main ship, and use the total amount of thrust blocks to calculate total thrust, thrust:mass ratio and power consumption.
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not fixed
Previously, the inherited thruster entity had the advantage, currently (0.19544 dev), the non-inherited thrust setup has the advantage. In my case I tested using 8 thrusters for each setup. Both setups had a mothership entity and docked entity (2 cores, 8 thrusters, a rail docker and basic rail), the difference being the inherited thrust setup had the thrusters split evenly between mothership and docked entity. The resulting thrust was 20.2 for the mothership having all thrusters and 15.7 for the inherited thrust setup with thrusters split evenly.
Ideally the thrust should remain the same and only depend on the total mass vs the total number of thrusters then apply the diminishing factor.
As a side note the docked entity should use its own power tank before drawing from the mothership for purposes of inherited thrust.
https://youtu.be/_F7eoDJOVdU