HBA1c test results are usually higher than meter averages. The process by which glucose binds to the haemaglobin is not uniform throughout the day and so, even if you did by some miracle, get a perfect average on your meter, it will not have the same distribution in time as the binding process. Furthermore, the binding process depends on several other factors which have nothing to do with blood glucose levels.
Also, HBA1c measurements themselves are variable so I wouldn't worry unless there is a trend over time. One reading does not make a trend. It doesn't mean that you are losing control. People tend to think of HBA1c as stable because it doesn't change every 5 mins like blood plasma glucose levels, but it does nonetheless oscillate over time. As long as these fluctuations are within range, there is not a problem. Even if one is out of range, it is not necessarily a problem. It's only when it is constantly above the upper end of the range that you have to think about what may be causing it.