Yeah, add it after the levels. But just to be sure, I'd put a line break between the commands, like so:
[command]
command = practice
exec = exec practice.cfg
desc = Locks the server and puts a pass on it
levels = 8 9
[command]
command = endpractice
exec = exec endpractice.cfg
desc = Ends practice mode
levels = 7 8 9
And so on. I don't think this will actually change anything, but it does make it easier to read.