Regulator service is not encouraged in the dive industry. Primarily of course because it is life support. Having been around this world for 55 years i can tell you there are adults out there that should be observed when they are changing batteries in a flashlight not to mention their use of power tools. The stuff I've seen people that supposedly know what's going on or should be is flat out scary.
It's kind of funny that absolutely anyone of any age can walk into any auto parts store and buy every component necessary to rebuild the brakes on his car or anything up to a tractor trailer or school bus with zero training and put it on the road with know DOT inspection and drive that 3000 to 30,000 pound vehicle down a freeway any where in America. But you can't buy a $30 rebuild kit for your regulator that can kill only you if you do it wrong. Oh well rules are rules.
Another obvious deterent for manufacturers to make rebuild kits available for the general public is our litigious society that we live in. HOG really has to be commended for doing what they are doing. They obviously have spent many hours with their lawyers before releasing the class to the general population that's why they have several unwaiverable stipulations for attendance in their class. As mentioned , reg repair is not difficult. There are factory repair/rebuild manuals commonly available on the web for many models.
The HOG class sounds thorough. Click on the link to read about the class. be sure to click on the link for the tool list. You will spend a good amount of money on tools and equipment.
http://thedecostop.com/forums/showthread.php?t=44947&highlight=hog+regulator+repair+class
You need to ask yourself , how much will I save by doing it myself with respect to the investment in training and tools and how long will you be diving /
One thing for sure as we pretty much all know for used sports equipment for any outdoor sport is ... that you can easily turn that $5000 dollar investment into $50 cash. The price you get for used stuff is just incredibly low.
All that being said. I built myself a way more than necessary air flow bench because I am an addict to tinkering with any sport I'm into. I have to live it, eat it , breathe it, sleep it. If you do a search on my stats you will see some pictures of the extremes I have gone to. I work in a machine shop so I can really get ridiculous. That was one of the things that was a negative when I was skydiving, there was nothing I could build to satisfy my addiction while not jumping.
There is a good school in Florida that is a week long that teaches theory and also has you on the repair bench for several days . It has gotten great reviews from friends that have gone to it and the factory schools. They were not impressed with the factory schools at all. I have been to a few of the factory schools and the really are lame. Most of the classes don't even have an IP gauge or magnahelic with them. They sorta mention it but nothing for hands on. I guess it satisfys the lawyers that you have been "trained". Scubapro has started making some repair videos that are very thorough for some of their models. Videos are expensive to professionally produce. Aqualung used to have most all manuals on the tech section of the Deales Section of their website. They are slowly eliminating them. What they are doing is charging you to take a online class on each specific stage i.e. first stage, second stage to be able to get the specific repair manual. Another way to generate revenue. I suppose you can't blame them. The cost of insurance for any manufacture of any product is staggering so they have to do what they can. The course costs aren't high but for a shop to buy them all for a product line could be costly.
Granted a lot of regulators are very very similar, but in court when the attorney asks if you took that products course "or one similar" you are really jepordizing your case. Unfortunately the shops have to be concerned about that as well. The chances of an experienced reg tech doing something wrong is slim. But stuff happens. It's easy to get distracted and forget to tighten something etc.
Good luck. Think about the cost. If it's a matter of the annual fees for the rebuild it may just be smarter to get a part time job here and there just to pay for reg service.
I do it myself because I don't like anyone touching anything of mine. In the last two homes I've owned the only person that has come into my house is the A/C guy. Only because I have not taken an HVAC course. I have all the tools to do it but need the training. There again, for as seldom as I need A/C service it's hard to justify getting the training. With the exception of the A/C whenever a company would call me to sell me an extended contract for a product , my reply was and is " I can fix anything, from a lead pencil to a space shuttle. Your product falls somewhere in between".
Good luck.