I'd like to know how probabilities are calculated for several effects of the same kind in a row, if I may. Especially Cast spell, because that's the most common and confusing case. I know that probabilities can be rolled for at once. For example, if I want a fireball spell to be cast on someone 30% of the time, cure light wounds another 30% and 40% bless, I would arrange the effects like this:
Cast spell - 100-70 fireball
Cast spell - 69-40 cure
Cast spell - 39-0 bless
Let's not quibble about percentile points, basically that's the order. The engine then makes one roll and, depending on where the die ends, the target gets that spell. But what if I have other Cast spells in the list? What if I want, in addition to these breaks, the target to always be hit by an extra fireball? Then I would write (I suppose):
Cast spell - 100-0 fireball
Cast spell - 100-70 fireball
Cast spell - 69-40 cure
Cast spell - 39-0 bless
Are those going to be two separate rolls - first always for one fireball, and then the choice between three spells? And would it matter in what order I put the three related effects? How about this:
Cast spell - 100-70 fireball
Cast spell - 69-40 cure
Cast spell - 100-0 fireball
Cast spell - 39-0 bless
Would this make a difference? And then, what if I want other effects entirely, for example:
Cast spell - 100-50 Use EFF
Cast spell - 100-50 Use EFF
Cast spell - 100-40 Use EFF
Cast spell - 100-70 fireball
Cast spell - 69-40 cure
Cast spell - 100-0 fireball
Cast spell - 39-0 bless
Would the engine roll once, twice or thrice in the case of Use EFF? Assuming that once, then a roll of 75 would trigger all three Use EFFs. If twice (supposing this because the first two are identical), then there would be one roll for the first two and another for the third. If three times (treated separately), then it's another possibility.
Which is it? And does it matter if the EFF is the same or not?