The CORE match percentage is calculated based on a distance algorithm.
The essential parameter in this algorithm is "the distance to zero" (DTZ). For the STEN scale used in CORE, the DTZ is 3 STENs. This means that a score of 3 or more outside the set Criteria will give a match of 0%. Any score within the Criteria will get at match of 100% and for each score outside the criteria and until DTZ the match percentage will get progressively lower.
The match percentage decline from 100% to 0% is not linear. The match percentage goes from 100% to 80% the first half of the distance to zero, and from 80% to 0% on the other half. Consequently, giving a relatively higher match percentage the closer the score is to the set Criteria.
If several solutions with match percentages set at the same time, the final match will be depends on which priority is set on the scales (e.g. a score on high priority will reduce more than if it had a low priority).