The bottom line is they got caught with their pants down! Quality tried to blow us off until another HVAC company said that the furnace was running way to hot - close to its shut off temperature. Only then did Quality come out and make a lot of modifications to try to improve the installation. And they still left the furnace out of spec in at least two areas - air flow and temperature rise!
We have suffered with a burning smell for two years that caused my wife health problems! And it took another HVAC company to finally resolve the problem.
So, don’t trust Quality’s design or installation, unless you want to spend hundreds of hours fighting with them and learning way more about forced air heating than you ever wanted to and possibly suffer health issues for two years too!
(And if you are interested, I can provide all of the sordid details!)