Rules are per season. The editor's tab strip lists every season of the series; each is in one of three states: own rules (the season carries its own scoring setup and can be edited directly), same as another season (read-only until you copy to this season and edit), or not set (start fresh, copy from another season, or inherit one).
Dependants. Editing a season other seasons inherit changes them too — the editor warns and names the affected seasons before saving. The same applies to a shared points table: a table can live once and be referenced by many seasons, so editing it recomputes every season that uses it.
Members and managers can both edit rules and upload results; only roster management is restricted to managers.