Official comment
I am not quite sure what you are asking. There are limits the the achievable accuracy using web maps. If you compare different maps sources you will see that they differ from each other by a few meters depending on where in the world the area of interest is. No one can tell you which one is correct either... That is one of the inherent problems in using a basemap as a reference for creating a new map overlay.
The coordinates you have called out should be enough precision to get within 5 cm or so.
If lining up with a basemap is your most important goal, using our basemap workflow will provide the best results. If you want to have a map with the highest absolute accuracy, the manual GCP recording workflow should be used (assuming a quality GPS receiver is used).
