it was not tdi sdi ......the agency got a call from the idc instructor he had 4 people on it and he went nuts when I told him a was an instructor Saturday night , I was already a naui instructor but I didn't tell anyone (I wanted the experience on the IDC not a crossover )..anyway the agency took it pretty seriously , as I passed I never looked back . the other first was that I ALMOST certified a Canadian icon singer , he never finished up the course but he didn't want any one to know he was taking the course as his "friend " was an avid diver . So he paid for a private course