Manufacturers can debit a warranty claim if it is determined that the technician recorded excessive efficiency during the repair (typically +125%) - excessive efficiency is an indicator of cutting corners or fraudulent repair practices.  When a manufacturer reviews/audits repair orders, one of the things that they look for on the accounting copy of the invoice is the actual time worked vs the time flagged/submitted for payment.  When they see a repair order with technician efficiency of 125% or more, a red flag is raised.  If you submit for "straight time" for diagnosis and the time flagged is over 100%, they will debit the overage... 

When is the last time that you sat down and reviewed your technician proficiency reports and compared customer pay/internal time punches vs. warranty time punches?  You may be surprised to find that you have more to contend with than just the factory if you find a trend of technicians not logging actual time for customer pay repairs...ever tried to justify a $1000 labor charge in front of a judge when there is no actual elapsed punch time to substantiate such a charge - only to be debited a labor extensive wiring job because the actual time for the customer pay job was run on the warranty repair order to "pad" the labor?

There are so many variables within Fixed Operations - and a manager is good to be able to control just the tasks necessary to manage advisors and technicians...why continue to use that valuable time trying to control your warranty department too?  Wouldn't it make more sense to procure the services of a professional warranty administrator?  Not just someone that warms up a chair in the office...but a REAL Warranty Administrator?!?