Not all aircraft are capable of supporting all of the Mode S DAPs, and as such certain information may not be available for downlink. There is no mechanism on the flight deck that I am aware of to inhibit supply of DAP - the transponder only has access to them if the avionics fit allows. This is quite common of some older airframes, which have been exempted from providing certain DAPs if not practical to provide.
From MACC Node-L Mode S info display point of view, an aircraft flagged as being ENHS capable means it is capable of providing at least one DAP, not necessarily all of them.
You should see compliance increasing over time, something like 85% of all mode S aircraft are now supplying at least one DAP.