I wouldn't have it any other way

I think if we choose the threshold column (of column where cell value starts exceeding value from PSPVDKUG) in that way, ECU will use it even when vpssplg_w is slightly less (but greater than axis value of previous column). Taking this into account, shouldn't we take axis value of previous column and make all scalings basing on it? Then ECU would go towards WOT & PID regulation only when vpssplg_w would really exceed the choosen threshold pressure ratio. There is almost no difference which column to take as basis, but IMO choosing and scaling previous column to the column where cell value starts exceeding value from PSPVDKUG makes the pressure threshold more sharp and exact.

You are absolutely right. The question was raised about which point of X axis better suits as base point for rescaling of the whole X axis for new WG cracking pressure.
On my opinion (let's discuss it) it's better to choose previous point of X axis (from previous column), the point where cell values haven't started to exceed the PSPVDKUG threshold yet. In other words, this has to be right-most column where cell values still do not exceed PSPVDKUG. Because our goal is to define in X axis exact threshold (= WG opening pressure) below which ECU doesn't go WOT. This means in the cells under choosen point of X axis you still have to see cell values which do not exceed PSPVDKUG. Remember how ECU searches axis values, it finds the least greatest value. Therefore if in column with your new WG cracking pressure there will be cells with values greater than PSPVDKUG, ECU will go WOT earlier, when vpssplg_w is less the axis value.

What to do if from stock in PDKSD , all values already exceed VDKUG ? CWPLGU is set to zero ?

Comments highly appreciated - thank you