how does Back side Mismatch losses are calculated in the Pvsyst ??

[PAVANAELPULA]

I went through the result chart, and i observed that Mismatch losses due to String and modules are directly proportional to the given input mismatch value in Detailed losses. However, for Back side mismatch losses, i could see different calculations were used. unable to understand, how the rear mismatch losses were calculated based on the input values at Bifacial system > Structural Shading factor & Rear Mismatch loss values.

Request PVsyst team to provide the calculation behind the output result percentage value of rear mismatch loss.