I really appreciate the feedback I have been getting on this. I've been wracking my brain trying to figure it out. Its been fun too. I've had to blow the dust off my turf degree. I know the setting is correct for the spreader and the product. I have a lot more experience determining the size of an area than I do spreading fert. However, I did ask myself those questions. The spreader is a Lesco 80lb Rotary Stainless. The product is Lesco is 18-24-12 Starter Fert. The product label info says LESCO Calibration Guage #15. I double checked it to be sure. I plan to talk with Lesco and calibrate this spreader. I'm more interested in the answers from calibrating than anything else. I have a scale on order. As soon as it comes in I'll do the calibration and share the results. Hopefully it will answer some questions. Your feedback will be appreciated again.