Currently in AST there is no way to change the severity of an issue. This can be accomplished in ACE, but the range data needs to be added to AST API.
Custom severity is important for numerous clients and issues. This includes advisory issues (lowest score), times where something may be technically incorrect but not an accessibility issue (lower score), or something that we indicate is a low priority but causes the entire site to be inaccessible (higher score).
Add the range information to AST API so that ACE can modify severity.