Don't worry meter is accurate this app is not 100% accurate gps messes too
and in your case look at gps in screen shot you have posted it should be 3m-5m
more accuracy but even if it is in 3-5m range still it some time messes too
i had thread to right about it but unfortunately i have not been able too
if gps meter had shown big error than i would have said meter is faulty
gps messes in cloudy day and also when you pass through road covered with tress it than also
gives error
i tested this with my cg dream at clean open road it showed meter and gps reading same at 60km/h
but when i was passing through road covered with trees it was showing speed of 56-57km/h and meter at 60km/h