Can a multiplier be raised after an event?
No. HQ sets the level at sanctioning; afterwards it can only reduce a multiplier or reject the event (×0). Every change is audited and the rankings recalculate.
Related questions
Answers follow the published KBN rules. The verify page is the authority for any licence or certificate, and where the rules do not cover a case, the Ranking Committee decides. Helpful counters on this demo site started from sample values.