TueorFortunam: reduced botch dices vs. no stress roll

Salvete Sodales!

10 days ago I got my copy of Hedge Magics, and this was bad, because yesterday was the date of my last exam (I neither spent as much time on preparation as I should have, nor could I go as thoroughly through the book as I wanted to). But now, as I have passed, it is time to start posting some thoughts I had, while reading the text. Given my well stated interests, most will be concerned with educated mages, just like this one:

The TuFa spell guidelines include two ways to avoid botches.
a) general - reduce number of botch dices by one for every magnitude of the spell
b) 10 - turn a stress roll into a open roll (0 counts as ten, reroll after a 1 and double)

I wonder whether there is any reason to use the general guideline beyond the effect for the first stress die, as for any other situation the second seems better.

Alexios ex Miscellanea

PS: Great book, thank you to the authors!