Yep started at a couple of those places too and it just about finished me and my dog. Which is why I shutter when people talk about 'fun agility' or instructors that one has to question their education and success.
It is so hard to convince people that by taking some time and learning foundations that the rest of the training is so much easier and FASTER. Both in time and speed. Not to mention avoiding stress and frustration for both. The more confident a dog and handler are the more success they will have and confidence comes with knowledge (and a bunch of other things too
Glad it is working out for you, good luck. Go Mia!!!!