Motoguy128, I agree that the conversation hasn't established the validity of the bills one way or the other. What was established though is that the customer believes they are "sky high" and that, in my way of looking at things, is always validity enough until facts are presented that prove things one way or the other.
All of us joining in on this conversation, being the professionals that we are, would have done minimal things if we were at her home to answer her questions. We would have done the heating load calculations, verified that the equipment sizing was correct, checked the controls to verify they were working properly in all respects, checked the equipment and every other part of the system to verify that it was operating and installed and functioning correctly. We would have provided her with the facts we found either verbally or written and then patiently walked her through the understanding process needed to grasp the information so that her perception could be replaced by these facts. Would things change or stay the same is anyone's guess at this point.
From the beginning her contractor has failed her. There were beginning issues with the install which supposedly were corrected. A second person was brought in to verify that the job was done right, but seems to have done nothing but do a walk through and make claims and suggestions that don't seem to have been backed up with any facts. The contractor has now used that "experts" observations to distance himself from his basic responsibilities as a contractor having taken this customer's money in return for providing a service.
I call them like I see them. The contractor either doesn't have the knowledge, experience or facts to personally back up his own work and explain to the customer why things are the way they are, or he simply chooses not to. Experience leads me to believe that he can't back up his work for any number of reasons and is hoping that human nature (of the customer) will just make this all go away and he can go onto the next job never learning a thing.
The facts are the only things that are going to ultimately resolve this issue for the customer one way or the other. Who provides these facts so the customer can finally have peace of mind is now the customer's choice.
To the homeowner, Minnish, I do hope that you find the answers and that you share your findings with this forum.
Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.