Post-treatment verification wash: 9 per 300 before, 2 after — does that count as "worked"?

Finished a full Apiguard course on my worst hive (of five) here in the Willamette Valley and did my verification wash yesterday, three weeks after the second tray went on. Numbers: 9 mites per 300 bees before treatment, 2 per 300 after. On paper that's roughly a 78% knockdown, which is about what thymol is supposed to do in decent conditions. But 2 per 300 is still 0.7%, and I keep seeing people say you want to be under 1% going into winter bee production. So — is 2 a pass? Do I re-treat with something else now, or just schedule another wash in a few weeks and watch for reinvasion? Other four hives all washed 0–1 after their treatments.