If I needed to be totally unambiguous, I might say something like "should be sent just before ...". On the flip side, sometimes the ambiguity is irrelevant, it doesn't matter which convention ruled it, if a bottle of milk claimed "Best f used by August tenth", you couldn't get https://titusjvdkq.thebindingwiki.com/8359131/not_known_details_about_best_prices_for_lumber