Hi,
I don't think the Tweaking.com utility cause issues.
The fact you were able to upgrade to Win10 1803 makes me believe that MS has indeed fixed the switchable GPU issues they had a while back.
Let's try the following:
Download the following
file.
Create a new folder on your Desktop.
Extract the file you've downloaded to a new folder on your Desktop you've created in the previous step.
Right-click
ResetWUEng.cmd file and select Run as Administrator.
A windows will appear prompting you if you want to continue with the process. Please press Y.
Another menu will appear. Press 2: Reset Windows Update Components.
Verify that you have selected number 2 and hit Enter.
Wait until the process is complete.
You should see the message:
The operation completed successfully.
Press any key to continue. . .
Close the window and reboot.
Try updating once again. If it fails with the same message, please attach CBS.log