This site states this directly: since nerve support is gradual, the 3- or 6-bottle option lines up better than starting small.
This site connects the package-size recommendation directly to its own stated gradual-timeline claim — worth reading that as a logically consistent piece of advice rather than a generic upsell suggestion.
Weigh your own genuine willingness to commit to several weeks or months of consistent use before choosing a package size, rather than picking the smallest option by default and re-evaluating too early.