I have a chart that gives you a rough idea of what the number should be. I also found if you do not get a sample of at least 30 lbs, you will not get very accurate results. If your overseeding, then you have entered a light number, so the rolls are going to revolve faster to put on more product.
I just set up for Canola, and using an extra fine roller with 6 runs, calibration rate should be between 60 and 70. Depends on the variety on seed. As stated above, I put two bags in for 100lbs to calibrate with. Primed the roller, then hit start and put just over 30 lbs in the collection bag. Came out to 60 which seems to be working just fine.
Your dealer should have the chart I use. If not, let me know what you are seeding, meter type and number of runs and I can give you the starting point.