After running the upgrade installer on windows for DLP, you change to a new service account within the installer, but this is not reflected in services after the installer completes.
The reason for this is how the installer works and this is by design. DLP upgrades happen in two steps.
Step 1 you install the new DLP version of the software.
Step 2 you run the migrator.
Its step 2 that actually does the upgrade. Step 1 only ever does a side by side install and is never an upgrade technically. So all you are doing is installing the new binaries to get ready for the upgrade to happen in step 2. This is why you see multiple versions of DLP installed on the system at the same time. Now because of this you cannot update to a new service account within the installer. As in step 1 we don't update the services as it's a working system. It's in step 2 that we will stop services but in step 2 you never specify the service username and password. So service account information will never get updated if changed within the installer.
It is recommended that if you want to switch to a new service account, you should do this before or after the upgrade is complete. Within the upgrade you should always use the same account that is currently being used in services.