That's part of the trouble caused when all types of diabetes are grouped together and assigned a single target. In general terms (now I'm doing it!), HbA1c targets are going to be quite different for a T1 when compared to T2, which for a T2 probably boils down to whether or not you are taking any medication to assist control of blood sugar.
For HbA1c numbers, the lower the better I would say, but not for a T1 where it's always going to be a compromise. There's nothing as accurate as a fully functioning endocrine system for correct insulin production, and trying to mimic this just doesn't work well enough. At the moment that is...