That shouldn’t make a difference, I always run adb reboot / fastboot reboot instead of using the menu when flashing devices 
But since I wanted to test what happens if you don’t reboot anyways, might as well test if there is different behaviour somewhere 
I’ll follow this up in the other topic, since I’m only testing FPOS on the other device for now.
Edit: Just to clarify this part:
get_unlock_ability gets reset on the first regular boot, so once you reached full userspace it’s already too late. Or did you mean something else with extended boot menu? 