App vs desktop not corresponding

[47p2]

I joined Fuelly a couple of weeks ago and filled in my car details, topped off my car and put the required info in. Today after 121 miles I topped up my tank and when I came home I put the details into my desktop PC and Fuelly told me I was getting 27mpg. However when I checked on my phone app it states I'm only getting 22.5mpg which after doing a calculation myself is not correct, 27mpg is the correct reading. Why the incorrect info on the phone App? (yes I have synced the app) Have I done something incorrectly when entering my data? How do I rectify this as I prefer the info on my phone

Desktop data


Phone data