It is unclear what purpose this field serves. In Student Assessment and Student Objective Assessment, the performance level provided in the data model (or API resource) should be the level met by definition - it is defined as "The performance level(s) achieved for the StudentAssessment."
This field actually introduces ambiguity - if the value is set to "false" and only one value is provided, the data becomes ambiguous. It both indicates meeting and not meeting the level at the same time.
Recommend removal, or clarification of why it exists.