These things are not the most accurate of devices.
I think sync up works very similar to devices like my ELM327 OBDII adapter which I use with my android and Torque Pro app. The sync up uses data and sends reports and my set up is self contained. However I know that all metrics have to be entered properly. Weight and units of measurements and engine size and tank capacity and etc.
I have read other posts regarding incorrect odometer mileage as well as MPG.
The ECM and PCM and adapter may all report slight differences. Also MPG may be instant or average. The only advantage this sync up has over the ELM is GPS tracking. Most people already have roadside assistance included with their automotive insurance.
These OBD2 adapters of any kind are a generalization of specificity. I considered the sync up long after I had already bought the $10 ELM and $5 Torque Pro app when it was free with adding a line. But again the info was too general and no way to add manufacture specific PIDs so specific to car generic codes can lead one astray as to the real issue.
I suppose wifi is nifty if none of your other devices can hotspot but a data plan bigger than 2GB is needed. Also the device is made by ZTE. Not a trusted name in many circles.
Wouldn't it be nice if the little SyncUP device gave you that extra MPG? We would sell a bazillion of them if they upped your MPG by 10 haha. In all seriousness though, if you are doing the math on it yourself using your odometer and how much gas you are putting in your jeep between each fill up and it is off by that much, we will need to get an escalation sent up on this. Please contact us when you have some time so we can get the ball rolling.
Again. The adapter can’t read the engine control module with full permissions so it goes on an assumed average.