Questions about Basic Craft System Successful Rate

Hi Everyone :)

The new basic craft system allows us to craft some items twice with same materials but double results in 1 trial.

For example:

At 5000-5999 Amity, we can craft 1 slot extender low, using 80 fcp and 40 extender circuits and 20 fchh
but if we are at
At 6000-6999 Amity, we can craft 2 slot extender lows, using 120 fcp and 60 extender circuits and 30 fchh

is the success rate different? Is it more likely to be successful at higher amity lvl (6000-6999) or lower amity lvl (5000-5999)?

Im hoping to hear your advice from anyone with experience or knowledge about crafting.
Thank you so much for reading :)

All fails like crazy

that doesn't sound good >.< but thank you for your reply :)