For what it is worth, in my experience with orchids and other plants in general, more often or not, when someone points to damage on a plant as being from excess fertilizer can often be traced back to insufficient water. Not saying this is your case, but I have rarely seen true excess fertilizer damage.
Your fertilizer program is very similar to mine, I use an MSU formulation and supplement with Green Dream. Dyna-Grow is similar in many way to MSU. I would continue with that program. Miracle Grow is something I abandoned years ago, initially in favor a Dyna-Gro, then later to MSU. So I feel you are on the right track with the fertilizer. I'm still trying to refine my system, but I feel, because I like to eat every day, I figure the plants would enjoy being able to 'eat' every day too. I am in favor of a continuous feed program. Once you figure a way to add a controlled low dose of fertilizer without spending a lot of time on it, it becomes easy.
One obstacle I had was poor performance out of proportioners that added a concentrated solution into the stream of water being delivered by the garden hose. I ended up setting up a tank, and a pump that could either recirculate the water in the tank (55 gallon drum) or to send through the garden hose. Now I fill the tank, add the fertilizer, recirculate then switch to the garden hose and water. For me it is quick and easy and the benefit of not having to worry about how accurately the proportioner was delivering the concentrated solution to the garden hose.
A malfunctioning proportioner could have been causing your problems with delivery of fertilizer, to much or too little, especially if the pressure of the water feed varies on you.
I'll be curious too to hear how things go next year. And I'll post how mine are doing too.