Depone, I suggest you visit your nearest ATC unit. I like nearly all of my colleagues work with a VERY open mind because we have to, so we can deal with situations such as a B767 being operated on a route filed to be a B737-400 which happened YESTERDAY! In the UK we do not and will not get aircraft type from Mode S data, you HAVE to state it, that is a mandatory requirement. Still haven't explained why it isn't pedantic to ask if you do not tell......