Traveling in the Astral Plane - penalty/bonus accumulation

[Axelmania]

Pg 39 of Between the Shadows gives a -5% penalty for "hopelessly lost" and a +10% bonus for "fairly certain". There are no modifiers for the middle 'uncertain'.

This is a gorgeous idea which sadly other writeups of AP (like Rifts, both editions) seem to lack. Without a mechanic like this it doesn't even make sense to have three different result categories.

What I'm wondering is: would you only apply that to just the next roll, or let these build up for ALL future rolls?

IE "fairly certain" next roll is 51 (usually "uncertain") but due to +10% it puts you at 61 for "fairly certain" and you get the +10% again...

Should your next (third) roll be +20%? Or just +10% again?

[Marcethus]

Pg 39 of Between the Shadows gives a -5% penalty for "hopelessly lost" and a +10% bonus for "fairly certain". There are no modifiers for the middle 'uncertain'.

This is a gorgeous idea which sadly other writeups of AP (like Rifts, both editions) seem to lack. Without a mechanic like this it doesn't even make sense to have three different result categories.

What I'm wondering is: would you only apply that to just the next roll, or let these build up for ALL future rolls?

IE "fairly certain" next roll is 51 (usually "uncertain") but due to +10% it puts you at 61 for "fairly certain" and you get the +10% again...

Should your next (third) roll be +20%? Or just +10% again?

There's a reason I use Between the Shadows as a Megaversal resource.

My ruling has been not to stack the bonus. They get the bonus only on the next roll.
I have had players fluctuate between hopelessly lost and fairly certain in the same trip.