I have removed all of them 1 foot above the runway without any loss of altitude.
Not dangerous at 1 foot but quite possibly a short cut to misery for family members when their budding pilot tries that at say, 500' on the approach after experiencing an engine failure... raising flap like that causes the aircraft to sink. Do you raise flap all in one go on a go-around? No. Or... at least I hope not!
Far better to lower full flap when you know yer can make the runway. Common sense ennit? Train your pilots to adjust the trim and maintain descent path from the start of Ex.13 - what do you want them to be? Pilots or robots?
VFE.