Question about sceneries P3DV4

[ideoplastic 86]

After installing FSDreamteam & Flightbeam sceneries to a folder outside the sim a new Addon Manager folder was created containing folders with xml files for each airport. I noticed the scenery.cfg didn't show the entries for these airports but that once inside sim if I selected any of the these sceneries they would be recognised and appear correctly. So far so good. My question is do all sceneries with xml files load into the sim each time it is started?  If so would the only way to stop this from happening involve removing the folders from the MyDocuments/Prepar3d v4 addons folder? I have always preferred controlling what I load to the scenery.cfg via the Scenery Config Editor Tool to avoid unnecessary sceneries not required for a given flight. Some feedback much appreciated.

I understand there is supposed to be information about this matter in the SDK, but I have not been able find it. 

Regards