I think my vet used an alpha-track too. I did 2 side by sides there with my relion micro, and saw a 30 pt difference. My vet told me on day one that my meter would be 20-30 points "lower than reality". I don't know if that is correct or not, but the whole time I was treating Bob, I always had in the back of my mind "well, that 79 is really a 109" and it influenced my decision to shoot or not shoot repeatedly. I always felt it was safer to shoot because of that 30 point difference theory. NOT sure it was the greatest way to think.
Eventually, I just had to adopt the theory that whatever number I got on the relion was "reality".
Carl