You're on their timeline, they're not on yours
. I agree with Tucker completely - sounds like the phals are growing well and they'll spike when they're good and ready. The nighttime temp. drop can't hurt so long as the temp. doesn't go too low, but it won't do the trick if the phals aren't ready to bloom.
I have certain phals that will skip a blooming cycle despite lower temps and continue producing leaves if they don't get enough sun during the prior growing cycle. You should check the light intensity where you grow your phals and increase the light if appropriate.
Hope this helps.
-J