The whole story is viewed through the adaptation values. On HFM and LH they are lower and upper partial load adaptation. These are multiplicative adaptations, meaning the fuel trim calculation is increased or decreased by multiplying the the number times the original calculation.
There is also idle (CTP closed throttle position) adaptation which is additive.
A rich condition driving down the road will aquire a multiplicative correction that can often not be needed at idle. This is where the final correction is added on top of the multiplicative.
The analysis is to look at all three values and see which one has reached the limit. The original programming gave a multiplicative correction from .85 to 1.15. The new program goes .68 to 1.32. I don't know if they expanded the additive idle correction but the amount is 1ms if I recall.
One should check all three values.
Bosch Master, ASE Master, L1
33 years MB technician