Not sure about your comment "close but not close enough". That is just incorrect, PPG formula, if mixed correctly, is perfect. If it didn't/doesn't match that is either the guy mixing or the guy with the gun who substitutes steps or a little of both OR someone chose the incorrect formula to begain with. You must use the product as instructions say, and a drop to much of any bases is reason to adjust the total finish amount or start over.
I have/was in that industry for 30 years, PPG Harley formula's are on the money, once again the guy mixing or the man with the gun is usually the problem. They make "close enough" in cars then blend to match. Has to be PERFECT on formula for Harley Colors.