I know the wording is ambiguous, but I'm gonna say it doesn't apply. I searched the forums and found a thread about this, where the general consensus was that it doesn't. But if you need further convincing:
Attached is a table of expected numbers of hits, for dice pools between 6-12 and edge 1-6. In the top table, the cases in which re-rolling beats adding edge before the roll are highlighted, without rule of 6 for re-rolls. The bottom chart is the same, except that the rule of 6 is used for re-rolls. As you can see, In the first case it's a wash, 50/50. In the second case, re-rolling has a clear advantage. If anything, it should be spending edge beforehand which gets an advantage, since you're doing it before you know the results. Allowing the rule of 6 for re-rolls would throw off the balance.