It happens that the taxes and the cost of an items varies on the vendor purchase invoice than what is in ERPNext
If the cost of an item is higher(lower remains to be tested) on the vendor PI, than you create a MISC items equal to the difference in unit price. This will solve the unit cost difference.
Taxes – when the taxes are different between the ERPNext and vendor PI, then there are two options:
1a – create a new entry for each of the taxes(GST, PST and/or HST) for each tax affected. Under tax type, choose “actual”.
1b – Enter in the amount that will balance out the difference.
or
2a – erase the listed sales taxes.
2b – add new taxes, and under the 1st column, tax type – put actual. Put in the “actual” tax amount you need.
Tax and cost adjustments-purchase invocie