Simply spoken- because testing is something else than taking a quick look if it seems to work.
I do not have an engineering department,I do this all by myself besides , website, sales, service, support and forum work......it´s a long day believe me....
The lenses on my List I have either tried or I own them and use them all the time.
It is not so easy getting all these highend 3-5 k lenses home to try them out in detail.
I have also already tested the Canon line of Superteles (2,8/300 and so on) and these do NOT work, which I mentioned- the reason is the
last lens is too deep in the barrel, thus we have barrel vignetting.
I am just now working on the usage of the Canon ApoTeleconverters with the HCam, which seems to be very promising, more of this later.