Arca-Swiss clamp and plate cross-compatibility is a well-known issue among camera manufacturers. There are dozens of manufacturers in the marketplace and 2 distinctly different variations on the style.
The original Arca-Swiss plate and clamps (as on the Arca-Swiss B1 ballhead) is followed very closely by most Chinese and Pacific Rim manufacturers such as Markins, Giotto, Vanguard, Sunwayfoto, etc. These generally feature a thinner plate (with a shallow V-groove with a 45 degree included angle, so the plate can only be mounted from the bottom into a clamp).
North American manufacturers (Jobu Design, Kirk Enterprises, Really Right Stuff, Acra-Tech) have moved away from the original design and approach a different 'standard'. Plates appear to be commonly sourced from 1.5" wide by 3/8" aluminum stock (give or take) and (usually) have a full 90 degree V-groove (dovetail) on the edges of the plates. This allows the clamps to be installed on the bottom or the top of the plate.
Our Jobu Design clamps follow the North American version with an unofficial 'matching' of the Really Right Stuff lever-action clamps, which we have confirmed with their engineers. We repeatedly test our plates against customer samples and produce our plates with go/no-go gauges to ensure we have consistent output in our machining. However, we absolutely DO NOT guarantee fit with ANY other manufacturer's plates or clamps. We simply cannot guarantee it, neither will they guarantee our system will fit theirs. We all operate independently.
Our Jobu Design clamps are designed to operate in a much wider tolerance band than most clamps with a very generous clamping range. We only use a clamping knob (no levers) on our gimbals since it is well known that customers DO mix plates and clamps. With an average cost of $5000-20000USD of equipment mounted on our gimbals, we cannot put any faith in cross-matching plates. Use of lever-clamps is highly UN-recommended in our gimbals.
So what is a customer to do? Stick with one manufacturer, or test out your plates in a safe environment to make sure they clamp safely with adequate overlap of the dovetail. If they don't fit, don't use it.
We'd like to see a new North American Camera Clamp System (NACCS...?) offered as a true standard, with published sizes and tolerances. Anything else is certainly misleading to the consumer.
-- The Jobu Design Team--