First, this may be of interest...
TCAS Bulletin
Second, you might contact John Law at Eurocontrol - I won't publish his personal address, but
[email protected] will reach his team.
Third, I have a feeling that the Bluecoat organisation discussed this a while ago, and a definitive answer (in your favour) was reached, but I can't find the thread just now. You could take a look at
Bluecoat and pose a question to one of the administrators.
If the company insist (wrongly) that you should not climb above 390 for TCAS, why not restrict yourself to 380 as a maximum? Suggest to your colleagues that they should do likewise...
Finally, might we have a hint as to which company is involved (PM me if you prefer)?
All the best,
AD