I tried to reproduce exactly what you did:
- Copy the same subset of DK scouts to a new atlas
- Compute the PLV for a single file using both the full DK atlas and the subset
- Export the first frequency band to a XLSX file
I obtained exactly the same values for the same couple of ROIs (see screen captures below).
Make sure that:
- You use the same files
- You used the same options
- You did not alter the DK scouts in your modified atlas
- You exported the same frequency band to the .xslx file
