It's common knowledge that the electric engine helps the main engine while travelling, but how much?
The new version of Torque Log Analyzer has a couple of charts that may answer that question.
The Electric Aid chart shows how many Amperes flow from the HV battery to the electric engine while the petrol engine is on. This current is used to enhance the power given by the petrol engine to the car.
Note that this chart doesn't include current used for EV mode, just the one used to help the internal combustion engine.
Some current peaks are observed primarily when the engine starts, but there's some little contribution even while cruising.
There's a small but somewhat constant electric contribution to the cruise.
It would be interesting to check if various SOC levels lead to different available currents.
This may require a long and varied trip to check out.