iPhone - Apple Maps / CarPlay - data usage (cellular data) - 1.2 GB with Apple Maps within two weeks, but a more detailed map has a file size of only 80 MB

Hello all,

for the last two weeks Apple Maps downloaded about 1.2 GB of data when using my iPhone (iPhone SE 2nd. gen) with Apple CarPlay (only via cellular data). The map setting was only "Driving".

The file size of a much more detailed map of this area (compared to Apple Maps) is only about 80 MB.

Traffic data in these two weeks cannot close this gap between 80 MB and 1.2 GB, as current traffic data is in the range of kByte.

Additional info: Apple System Services on my iPhone had a data usage of about 800 MB within this two weeks (only via cellular data).

What could be the reason that Apple Maps has a data usage of about 1.2 GB for the given area when a more detailed map (and more up-to-date map) compared to Apple Maps is only about 80 MB?

Thank you.