How much is normal for the Dexcom to be off from the BG meter? I just started my very first sensor yesterday so I am still in the first 24hours, but it seems like the sensor readings are 20 points or more off of my meter results. Does it help to continue entering meter readings to the dexcom to help it be more accurate? Or should I just do the 2 per day and hope the accuracy improves? Any help is greatly appreciated.