Please read more closely. One state says
" Prior to the fifth Monday of the competition season (September 17), meet managers have the option of running a 4000 meter course for competitors below the varsity level as long as all varsity and sub-varsity races run to a common finish line. Beginning the fifth Monday of the competition season (September 17), all competitors must run 5000 meters."
So for the majority of the season, they have to run 5000 meters. No other distance is allowed. Even before Sep 17, 4000 is allowed for below varsity but no other distance other than 5000 is. Every race after Sep 17 is 5000.