Hi !
Benchnmarking is OK, but only the sides you have for comparison are the same.
For example, in production of populating PCBs, you can get significant differences if you have products on witch you must place 50 components vs. ones with 300 components. Even if you do a calculation of efficiency based on placed components, still you will have a better yeald for the small qty. ones.
Also, for the whole location, depends on the products portofolio - a larger portofolio of products means more may CHOs.
Also, lesser CHOs and high quantities allow you to work with 1-2 people per SMD line - and this personel figure you cannot compare with a plant with lots of CHOs.
It's a tricky thing when presented to world wide management. Maybe that's why each location finds methods to cheat the system/reporting. On our example, some do the calculation of efficiency with maintenance and downtime due to materials problems included, some don't - and all in the same company.
Further more, if there is a world wide company, it;'s hard to know the exact situation on each plant - and you know everybody wants to look good in the reportings !