The tourists face a much tougher task than it initially seemed to usurp England at the top of the table in the three-match Investec series set to get under way at The Oval next week.
Up until Saturday morning, when the ICC's revised calculations were published, Graeme Smith's team trailed their hosts by just one point.
But the elimination, from the relevant mathematics, of South Africa's series victories in England and Australia four years ago means they have dropped from second to third.
England remain at number one, with six points to spare over their new nearest pursuers Australia and nine in front of South Africa.
Andrew Strauss' world-beaters have moved up five points to 122 but can still lose their table-topping status over the next six weeks.
Even a 1-0 or 2-1 defeat to South Africa would see the victors go level on points with England, but above them by a decimal fraction.
Should England either draw or win, though, they will stay on top - and if they were to whitewash the tourists, South Africa would drop to fourth.