The Brain-Preference indicators from the AVI are based on a Systems Science Model of the brain developed by Walter Lowen. There is a clear "audit" trail from Lowen's work to our implementation.
The correlations between Brain-preference and values are reported in New Wisdom II.
As for reliability, for starters the AVI is simply an inventory of a person's values, and as such, just reflects back to a person their current choices which are expressed as current priorities/preferences.
If a person's choices change over time the AVI report will be different.
The questions then are: Has the questionnaire reliably reported the person's choices? (the answer here is yes as the there is a one on one relationship between the statements chosen and the values chosen) and, has the person reliably identified in their mind what is now important to them? On the latter point - the AVI is not a psychological test instrument - it is a map (for self-exploration), not the territory. The instrument is designed to aid people in the process of "individuation" - i.e. discovering through experience and reflection, one's uniqueness.