Another thought on what the hell Tranmere are on about:
Each club is given a best and worst case scenario based on applying both the same higher margin for error figure and the same lower figure to the additional ppg for each club. So each club has a predicted range of possible points. You then look for "overlaps".
So Donny, for example, would have a maximum points total of 74.27 on the highest margin for error figure. This would get them into the top 6 if clubs above them had the lower figure applied. So Donny would get into Tranmere's extended play off group. Ipswich even on the highest MFE figure wouldn't be in the top 6, even if the team's above them had the lower MFE adjustment, so they would miss out.
I fear that it may be even more complicated. Sorry