We NEVER use balance rates to condemn Injectors, We do at times use them for touch tone info...Any shop that condemns HPCR Injectors solely on balance rates is trying to reach in your wallet. Return rates are much more reliable... Now watch out for shops that condemn Injectors when testing....If they test Injector(s) to meet NEW spec's used injectors will likely fail, than they will throw the fear card. Fact if your engines shows NO sign of issues there good, Vibrations, surging, hanging RPMs, Smoke, Long/No start, Combust knock, .05+ fuel OAs, horrible Mileage, are the most common, Now that being said if you have Injectors at 200K+ miles plus the 1st sign of issue(s) it wise just to replace them.. Don't waste $$$ on testing thats going to confirm what you already know.