Why did my queries change between scans, and why do repeat scans reuse them?

A second scan of the same brand reuses the first scan's query set rather than generating a fresh one. This is deliberate: two scans that ask different queries cannot honestly be compared, and an apparent score collapse that is really just a different test is worse than no trend line at all.

What changes it

A bigger plan adds new queries on top of the kept set, matched by intent so the original ones are never silently dropped. A smaller plan (for example a paid brand falling back to the free plan) trims from the end of the plan, keeping the highest-priority buying queries first. Free-tier accounts reuse queries by domain, so the same test can run again even with no saved brand.

Pinned and scheduled queries

Any query you pin yourself (Queries page, "Manage questions") is fed into every future scan ahead of generated ones and is never dropped by trimming. A scheduled scan uses a frozen query plan set when it was scheduled.