Greater Shadow Conjuration+Crook of Cidhureen=110% effective?

[Reksew_Trebla]

Crook of Cidhureen. A full 5 charges adds 50% to the disbelieved effectiveness of a shadow spell. Greater Shadow Conjuration has 60% effectiveness to start with. This means it goes up to 110% effectiveness when disbelieved. Add in Solid Shadows with Spell Perfection, and it goes up another 40%, to 150% effectiveness when disbelieved. This can’t be right, can it? Please tell me there is a FAQ preventing this.

[Dαedαlus]

Don't forget your Shadow-blooded sorcerer capstone, for another 20% effectiveness, for a grand total of 170% effectiveness when disbelieved.

To be fair, the staff is a bit pricey for what amounts to 1 super-powerful shadow spell every five days, but so far as I am aware, it is RAW.
(Without the staff, you can only get to 120% effectiveness on a successful save.)

[Fuzzy-Wuzzy]

Trying to get the GM to actually apply greater than 100% effectiveness sounds like a good candidate for this thread.

[Claxon]

Yeah....this seems like an issue that when the abilities were written no one considered the possibility of stacking them. It's probably not intended to have more than 100% effectiveness.

Certainly as a GM I wouldn't let it be more than 100% effective whether or not it's disbelieved. Especially since you would have this weird thing were it's actually less effective if you believe the spell is real than if you disbelieve it. That's just super weird.