Add-on, the official ruler: the band and threshold ladder published by the source agency, its classification, and distan

Add-on, the official ruler: the band and threshold ladder published by the source agency, its classification, and distance-to-action. NOT every line has an official ruler - pure market quotes do not. When it does not, you get 422 with no_charge:true and reason:no-ruler-for-this-line and you are NOT billed. Never a bag of nulls you paid for. Every record carries an offline-recomputable record_hash.