Never been 100% sure either way
BUT I was taught that if you change whilst on ALT do it as follows
away from 7000 by changing the high order first (for example if going to 3006) change the (7 to 3) / 0 / 0 / (0 to 6)
towards 7000 by changing low end first (example to revert to 7000)
change the 6 to 0 / - - / 3 to 7
by doing it this way you cannot go through the emergency codes ...
bit of a phaff to remember at first but becomes instinct after a while and seems to work