I don't think it's as accurate if it's not reading .00.. Mine stays pretty close when I take it off the windshield, I try not to jar it to much. Mine will say .00 then I push the "GO" button and it flashes .01 or -.01 so I'm not sure how much that effects my times. They are very sensitive!
Jim

 

it will ''generally'' tell u what ull run, thats all that matters