QUOTE
A spell’s Force limits the number of hits (not net hits) that can be achieved on the Spellcasting Test. So if you cast a Force 3 spell and get 5 hits, only 3 of those hits count. In other words, Force has a limiting effect on spells—the more oomph you put into the spell, the better you can succeed with it. This limitation does not apply to Edge dice that are used to boost a spell.
So... what uses of Edge does this cover? Is it only Edge to add dice to the dice pool? Or does rerolling all dice that didn't get a hit also count for this?
For example, say a character has 3 Edge and 12 Magic + Spellcasting to cast a Force 5 spell.
If the character gets 4 hits and uses Edge to reroll the other 8 dice for another 2 hits, does the spell have 6 hits or 5 hits?
Alternately, if the character spends Edge beforehand to roll 15 dice and gets 5 hits on Magic + Spellcasting and 1 hit on Edge, and gets another 2 hits from Rule of 6, does the spell have 7 hits?