In version 6.0 and higher, changing the VAT rate requires two visits to the Setup Wizard for labs that have the “VAT is already included in prices” option enabled.

The steps are the following:

  1. Inside the Setup Wizard turn off “VAT is already included in prices” in the VAT Settings.
  2. Change the “TOTAL VAT Rate” to the new rate (Ex. from 17.5 to 15.0).
  3. Save and exit the Setup Wizard.
  4. Re-launch the Setup Wizard and click on the VAT Settings option on the left.
  5. Turn the “VAT is already included in prices” option back on.
  6. Save and exit again.

See screenshot for reference: