deanoNerd wrote:Does the update script check to ensure that it only applies updates since the release of Windows 10 1909 for my situation?
This has been asked countless times, and the answer is still the same: All updates for the selected plattform are downloaded, regardless of whether or not they're required. This ensures that you can update systems to a defined state regardless of their initial patch state, i.e. more up-to-date systems will install fewer updates.
Does it make sure that it does not spend time re-applying old updates that are already integrated into Windows 10 1909?
Yes. WSUS Offline tells the Windows Update Agent (WUA) to search for updates and only applies those that the WUA defined as missing/required.
PS: If you want some mechanism that only downloads updates for your specific system, WSUS Offline is the wrong tool, but there are others out there (WUMT comes to mind, but IIRC it's currently unmaintained).
Regards
Dalai