Tourist im surprised that 50% of the people here can't understand your question. Talk about frustrating!
I understand completely what you are asking.
At application of Flex / TOGA Time =0s, even T=2s there is bugger all airflow over the THS.
You can go full up on the elevator and it wouldn't do anything.
In short the FCTM should say go elevator down at ~40/50kts. However us Brain Surgeon Pilots might forget. So we do it at the beginning .
Simples.