Rob I have the TDI extended range course material and the Decompresion Procedures and Normoxic Trimix they are all about the same when it comes to decompresion planning using accelorated high 02 mix.
Extended range was writen back in 1999 and even thow that wasent long ago it is well out of date and IMHO aimed squarley at deep air diving. There is even a dive plan in there for a 60m air dive for 30min bottom time. Most people today call this madness.
Like you I had done over a years accelorated deco diving using two stages in some cases. As a result my Deco procedures course lasted one day and two dives. I walked away having lernt that Atrixo hand cream is very good at helping you get your gloves on and keeping your hands warm during the dive.
The entry level Trimix course was writen in 2002 and is a bit more up to date. It was all about dive planning kit preporation and skills and I throughly enjoyed it but more importantly it opened up 50 -70m clear headed diving so it felt a realy usefull course too.
It is a bit irritating to have to do another course to go full trimix but you can understand that they dont want divers droping down to 90+ on their first go at trimix.
My instructor did a deel on incorperating the Deco Procedures and on the upgrade to full trimix so have a chat with them and see how you get on.
Just a thaught
Mark Chase