I am using a hack that displays the altitude on the screen on my F700BT. When I park in my garage the altitude reading is different every time. Here are the last three readings 4612, 4632 and 4541. Goggle tells me 4597. Is this normal or do I have a problem?

I am using a hack that displays the altitude on the screen on my F700BT. When I park in my garage the altitude reading is different every time. Here are the last three readings 4612, 4632 and 4541. Goggle tells me 4597. Is this normal or do I have a problem?

Within normal error range, particularly for altitude (you need more satellites locked to get altitude reading). Also, inside a garage you won't get too accurate a reading anyway.