Can`t catch the logic of stimulators.

[jackyurchiksparrow]

Minecraft 1.7.10.

According to wiki, max amount that alveary can have out of stimulator for production is 1000%. I have a rusty bee and their production amount won't change after 750% while valuable bees' production keep growing even after 1350%. I found a formula for productivity with frames. Is there anything similar for stimulators to know if there are any sense to add more? Thanks for you time, looking forward to hearing from you soon.