If you post a link to a sample SPP 6.0.2 image, I can see what might be going wrong, in particular, whether it's an issue with LR or with SPP.
With Edit Capture Time, the instructions at the top of the window (see the screen shot above) explain how to do a batch correction: Select multiple photos, do Edit Capture Time, correct the time for the photo shown in the window, and the other selected photos will all be adjusted by the same amount.