This site labels its two larger packages differently — "Best Value" on 6 bottles, "Most Popular" on 3 bottles — worth understanding what each label is actually claiming.
"Best Value" is a price-based claim, tied directly to the 6-bottle package's lowest per-bottle cost; "Most Popular" is a different kind of claim, about purchasing frequency rather than price — worth not conflating the two.
Like the 93%-choose-6-bottle-kit stat elsewhere on this site, the "Most Popular" label appears without a linked, independently verifiable purchasing-data source — worth reading it as brand-stated context.