What is the point of the spell Probability Prediction?

[Malenfant]

What is the point of the spell Probability Prediction? Is there something I am missing? A combo somewhere that makes this spell be useful?

[Rysky the Dark Solarion]

Uh, it lets you reroll a d20 roll, that's pretty blatant in what it does and it's extremely useful.

[avr]

If you really don't want to fail a roll - say it's a computers roll which will trigger alarms if you do - it's excellent. A reroll is approximately the equivalent of a +3 on average. Between +1 and +5 depending on your success chance without the spell.

[Malenfant]

Rysky the Dark Solarion wrote:

Uh, it lets you reroll a d20 roll, that's pretty blatant in what it does and it's extremely useful.

Yes, but you must choose to do it before you know the result of the first roll, and you must keep the second roll, even if it is worse. How can that be useful?

Eg. "Character triggers Probability Prediction, rolls a computer check die (18), now must re-roll (7). Character is stuck with second roll.

Or am I misunderstanding the spell?

[David knott 242]

It is the standard language for reroll powers. It can be used after you know the number rolled but before the GM tells you whether the roll succeeds or fails. Your GM will need to learn not to announce successes and failures too quickly when such powers are in play.

[Malenfant]

David knott 242 wrote:

It is the standard language for reroll powers. It can be used after you know the number rolled but before the GM tells you whether the roll succeeds or fails. Your GM will need to learn not to announce successes and failures too quickly when such powers are in play.

I see, now I understand. Thank you.