Please create a PO in MRPeasy in the same way that you would create a bill in QuickBooks. If you do not enter a tax separately when you are in QBO, please do not enter it in MRPeasy either.
QuickBooks has localizations with different functions. For example, in the Australian version of QBO, it is possible to configure taxes such as 'Collected on purchases' and 'Purchase tax is reclaimable'. In addition, a bill has a separate field for tax. In the US version this functionality is not available.