Question about FEV1

[blizzard2014]

Hey, I recently purchased a peak flow meter. It is an electronic one. I have had some widely varying PFT results from the full blown PFT inside the booth and some other tests at my GP's office. I noticed a big swig between numbers. I blow a lot of 1.89 FEV1's which is almost exactly what I blew when I took the test in the booth. I also blew two FEV1's of 3.10, which is about 78 percent of predicted for me, but I could not duplicate these results three times. The most reproducible results are never over 2.40 FEV1. But why was I able to blow a FEV1 of 3.10 twice two days apart? I also had two 600 PEF's, but most of them are 400. I also had a low FEV1 of 1.89 despite blowing a PEF of 600. Do you think this is all effort related? I didn't blow any better after taking Stiolto. I don't know what to think now as one doctor says I have COPD and the other says I don't? I have a lot of other medical problems as well that can cause weakness/tiredness and sometimes I am so darn tired. Maybe my lungs are good but I am too tired to blow properly? But with a high PEF, I am blowing hard. What do you guys think?