The Districts do not decide what counts or not, the Sections do. The only difference between Sections that I am aware of is in regards to "T" ratings. Generally the only "League" that counts (besides mixed exclusive) is what is known in the Southern section as the Spring League.
The October deadline is because the National Playoffs have just finished up for the "Spring" league. This needs to be finished before benchmark ratings can be factored in.
G4, Singles League does not contribute to ratings in the Southern Section.