It doesn’t error either way. It does what you tell it to do. My recommendation is to find your best run in the past that you have weather and fuel notes on and put that run into AP then take it to Bradenton Nd put that weather in and go from there. Another recommendation is to pick an RPM and gear such as 9000 in second gear or if you don’t go that high then 8000 in second gear and look at the data logger and get boost, fuel pressure and fuel flow if you have it and also put in what leanouts were on at that time of the run. You always want to use the same point in the run for fuel data. You can calibrate AP to show exactly the same fuel data as shown on the logger. If you have a flow meter then every run is a flow bench run. Make sure you download the instructions from the www.alky-Pro.com website and read it. You can also download a trial copy of the software and can use it for a short period of time to decide if you want to buy the license for it.