From the information I have (the original marketing spec sheets) this is definitely NOT the case.
Not all of the slots had the lower 91% as an option, while others didn't have the higher 97.5% choice.
Also, the "middle setting" was 94% on some slots, but 95% on others.
This points to them being able to adjust each game individually.
KK
Interesting. That sounds like it contradicts what I have been told by two separate RTG operators who both told me they had to submit to RTG which of the settings they wanted. My information is at least 2 years old though...maybe it's changed.