Faster on field, pulling a heavy cart when either VCA or GS guidance is enabled

[Gordon-Dry]

When not using guidance the engine usage and gear behaviour feels realistic, but when I enable the guidance from either VCA or guidanceSteering it's easier to get to the working speed.
I tested pulling a fertilizer spreader filled with 30,000 liters and I was hardly able to reach 14-15 kph without guidance, but as soon as I enabled guidance it's easy to reach the working speed of 18 kph with reserves on top.

I feels like as if the torque curve of the vehicle is replaced with a generic torque curve or something like that.

[Gordon-Dry]

Okay, it's different I guess, but still VCA:
It has something to do with the "engine modifictions" and the pto usage of the pulled cart - but it doesn't matter if the "engine modifications" are on or off.
As soon as I enable the pto - which draws power from the tractor - the tractor gets it easier to pull the cart over the field for some weird reason.
I my humble opinion it should be even harder, as not all the power goes to the wheels of the tractor anymore.