I have gone through the calibration process on my new to me 2340 air cart. I seeded 47 acres applying 90 pounds of dry starter out of the front tank and 100 pounds of seed out of the back. I followed the instruction in the manual and even calibrated it four times (twice before I started and another two times after having seeded some). I put the slides where the computer told me. The dry is reading dead on on the head. The dry is reading anywhere from 87-100 pounds. The seed is going through a new meter box with a new sensor on it. Do I trust the computer or is there another way to double check the seeding rate? Also, why the rate variation on the seed but not dry? Please help me.