Since EuroroCom (the certification authority) agree that TRT800s are fully compliant with the published standard, I believe Funkwerk/Filsers's interpretation was reasonable.
I also understand the published standard is now revised, since in congested traffic, mixed Mode situations some responses are missed.
All due to the standard being based on computer simulation, which oddly enough is what the CAA's Mode S consultation proposals are based on.
Makes you think (unless you work for the CAA............)