You just learned more in doing this than at any factory training school. Most of them only hit the highlights that I have been to over the years. You also just found out that sometimes mods are necessary to overcome a design flaw, even OEMs do this at times. They call it product improvements.
I am a self train fellow myself and I usually work rings around the local dealers as they techs are not that well trained or experienced. This doesn't mean that I didn't take 2 years of electronics training but most my mechanical training was done by my self father while I was a pre-teenager and continue by myself as you are doing now further training myself. I help rebuild my first V8 while I was in the second grade. Of course I don't know everything and I am learning new things all the time; none of us know everything. As log as you willing to ask for help when you need it is a sign of a good repairman. For me it is hard to get help with my problems as they are usually over the heads of most customer support personnel now and that is frustrating.
I personally know of several cases that the JD dealer even giving the completely false information and recently they couldn't even repair a Stihl hedger that was under warranty. I ended up having to fix it myself for the customer. I also got in several local shops supposedly repaired equipment last year that I had to redo. Mostly hack up wiring problems. Their screw-ups just make me look better and more profitable.
The truest measure of society is the how it treats its elderly, its pets, and its prisoners.