The convention is as you noted. However, “not” is a contraction of nought (the British spelling—American spelling is naught), he’s not too far off.It's "all for naught". That GRCC education is showing. Now if you had gone to WSU, you would have been taught the following:
https://brians.wsu.edu/2016/05/16/all-for-not/
But I’m sure he didn’t know that.