Just to finish this post off and for the benefit of those who were kind enough to advise.
We took our journey the week before Easter and arrived at Detroit about 40 minutes late, i assumed with that delay the people trying to connect with the early flight to Orlando would miss it but i was wrong.
Delta people were waiting at the door on leaving the aircraft and asking Orlando passengers to proceed quickly to security and immigration, at immigration Orlando passengers were being fast tracked through the crew aisle and then after baggage rushed to their flight. I was surprised about the fast tracking but immigration wasn't very busy at the time.Because we were on the later flight we took our time and i doubt if we would have got through customs and immigration in time to make the earlier flight without the offered help.
Quite a few people were trying to make the connection and with all flights being oversold it would have been hard for anyone missing the flight to be accommodated.