I didn't make myself clear earlier, sorry.
Uhmgawa is right, there is not authoritative definition on the loader's QA plate, just the attachment plate. As a result, Kubota should have reverse-engineered the QA plate. They should have reverse-engineered to a fault...to the point of noting the height of the receiving plate, angle of the back of the bucket, center of latching pins, etc. of several leading skid steer manufacuturers and aftermarket manufacturers who do quality work.
I'm sure that everything worked fine during R&D testing with Kubota-built attachments. But what if you stick a Bradco pallet fork on the Kubota loader or use a Bobcat skid steer bucket? I am not aware of New Holland, Woods, Bush Hog, or Great Bend loaders having problems with their QA plates not working...I wonder why? Maybe its because they did their homework.
Kubota did their homework...almost. And its the almost that always causes the trouble.