You're right, the numbers are 'off' and different; but if we drop into trend analysis instead of fixating on a single month the numbers, especially for those of RIM and other (many but not all) factory automatic replenishment programs (marketing and masquerading as inventory control) we see a much different picture.
1. An increase in overstock (excess stock)
2. An increase in obsolescence; they don't call it that because in many cases you can return the parts in 9-15 months; so it's really an free loan to the factory with your money.
3. No marked fill to the shop on demand for parts needed
4. A mix of parts based on a 'market area' and not the specific dealership; especially important to those whose dealerships are on the outskirts of large metropolitan areas.
There are some measurements that will help you to track what is really going on; go to
www.partsconsulting.com and download the checklist and the key to the checklist. No cost, no advertising because you downloaded it; it is free. The checklist, done monthly and then trended on an Excel spread sheet will give you a much more clear picture of where you are and what the inventory investment is really doing.
Mike Nicholes