Ambiguities in use of assessment performance levels

In mappings to the Ed-Fi assessment API, some ambiguities in how to use assessment performance levels has emerged:

See the data model: https://schema.ed-fi.org/datahandbook-v331b/index.html#/AssessmentPerformanceLevel484

First ambiguity

It is unclear what score is being referred to in Maximum and MinimumScore, as an assessment can have multiple scores. It seems like there should be some explicit way to connect what scores these are referring to.

Shouldn't there be a element that makes that connection explicit?

Note that this COULD be done via AssessmentReportingMethod (i.e., the Score AssessmentReportingMethod and the PerformanceLevel AssessmentReportingMethod match), but that seems risky / bad as, 

1. it means that each score can only have 1 set of cut scores/performance levels.
2. it provides no way to give a "human-readable name" to the performance level - you end up confusingly using the score name

Second ambiguity

Why even have ResultDatatypeType as part of AssessmentPerformanceLevel? It's optional, but it will always be "level" - why not just remove it?

Acceptance Criteria

Data model redesigns and/or normative guidance on how to solve these problems, attached to this ticket