Hello Ulli,
please confirm that you have configured your default determinations as AFTER_MODIFY determinations and as trigger condition only CREATE (and neither UPDATE nor DELETE) is checked. Also the request node of the ROOT determination must be ROOT and the request node of the subnode's determination must be SUBNODE.
If you have this configuration, your ROOT determination will immediately be executed if a new ROOT instance is created. The determination for SUBNODE will immediately be executed if a new SUBNODE is created.
If both ROOT and SUBNODE instances are created in the same service manager request and you would like to have the ROOT's determination executed before the SUBNODE's determination, you have to maintain that determination sequence on the corresponding tab of the determination's configuration.
Best regards
Tilmann