Tracking when I watered so I could predict when I would need to water next I learned a lot.
Counting from onset of 12/12, one might expect to see that during days 20 to 50 (ish) on a 70 (ish) day strain the plants "speed up on the drink". It's a sudden and drastic change in water consumption. For example in my own grow I might be watering every 24 hours on day 19 and then suddenly on day 20 they are parched after only 16 hours and I end up having to water every 14 - 15 hours until day 50 when they suddenly slow back down and are not thirsty until 24 hours again.
Gorilla Glue #4 for example, when I ran her she did her "peak drink" from day 19 or 20 to day 50 or 51 (from start of 12/12) and it was precise for her every round I ran her. Mimosa it is day 22 to 55 from what I have learned from her in a few runs.
I track when they are ready for water (peat based soiless mix bottle fed) using a soil moisture meter. That's how I determine when they are thirsty enough that I want to water them. I don't wish to overwater a "soil" grow because the soil needs to dry out enough before I will water again to allow oxygen to the roots. With coco of course you don't want it to dry nearly as much but it still needs to dry a little. By using the moisture meter I am hitting a consistent "dry" target and by watering the same amount each time I am able to observe the plants drinking more during that peak drink period. So if you are running RDWC I would expect the top off requirements to increase during that period.
Know that each strain is different and a long flowering strain may not have a longer "peak drink" (I like that term so please forgive me) phase or it may... Also know that overwatering a soil or coco grow by not realizing the peak drink period has ended and increasing the interval between watering can cause root rot during ripening. In extreme cases this can cause parts of the bud/s to die off without signs of mold or mildew and it can even cause whole branches or plants to die just before they are ripe. (wow time to go break up this one big paragraph lol wall of text just happened)