Keep in mind that there is no set rule for every grow, these values are merely guidelines for the grower to work with.
Your environment, how it behaves, what is interacting with, will have a lot to do with how things are set.
Also, your equipment is important as well. All that hardware adds to heat...
Different strains will also behave differently under set rules, you have to be flexible or "dynamic" as needed...
I'm working a 1200 plant GG with 10 rooms. Some of our biggest challenges are with equipment. As we add dehu's, heat is an issue and the a/c's can't keep up, things like that. Also, PM. Keeping things cool and dry enough at night to limit outbreaks...
But on topic, we run veg @65-75 rh
week 1 flowr @ 60ish
Week 2/3 is where we begin to work this down, 55ish
You can run this through week 5/6 around 45-55. your plants(strain) will show you what they prefer...Watch Them Closely.
With our feed program, we are getting massive bud swell late in week 6 into week 7. Dropping RH at this time and adjusting temps down in the last week is huge. The problem here is the DP(Dew Point). We do not have heaters in our rooms and temps are still dropping (outside) to -8C.
As the temps drop, so does the DP and the Dehu's are icing up trying to keep up. We are forced to increase day temps and RH just so we can get through the night before lights on. For instance, I have to keep my night temps above 70 and rh above 40, just to stay a step above DP so the equipment keeps running and reduce mold risk.
Sometimes, it's not so much what you want to do, but what can you do...