ahhh, and there you can see where their tech program was written by GUE guys.....
Too funny. Although NAUI tech and GUE are similar, Its not because the GUE guys wrote the NAUI tech program. Its because NAUI, IANTD, TDI, GUE and UTD basically branched out of the same core group of tech divers/Instructors. Each had seperate philosophies on how to teach, market and dive, therefore there are different agencies teaching the same core system with different methods.
If you had to group the philosophies together, I would say that there are 3 different groups:
GUE/UTD/NAUI
TDI/IANTD
PADI
Groups 1 and 2 are the closest in relation in my opinion.