To be consistent in your contract usages, you have to make decisions big and small. Here’s a small one: which to use, no later than or not later than?
Behold what a Merriam-Webster “Ask the Editor” item (here) says:
[T]here are differences in the way these two expressions are used. No later than is used more often than not later than, and it is less formal. Not later than is used mostly in formal documents, such as rulebooks, government laws, and academic papers.
Of contracts filed on EDGAR in the past month, 2,981 use no later than and 2,033 use not later than, so it’s a wash.
Given that the only difference is the level of formality, I’ll go with the less formal version. So no later than it is.