The Tax Basis field on the AP Unapproved Invoice Entry form, line items Info tab.
Entry in this field is not required.
This field indicates the portion of the gross amount that is taxable. If using tax discounts (flag in AP Company Parameters), the field default is the 'gross amount less discount amount' (if applicable). Otherwise, the default is the invoice's gross amount; may be overridden.
Tax amounts posted to subcontract lines are not included in the invoiced amount updated to SLIT (SL Items). Therefore, if you have set up a subcontract to include sales tax, it is suggested that you post invoices with the tax amount included as part of the gross amount and set this field to 0.00. If the subcontract is set up without tax and sales tax applies, then gross and sales tax amounts should be entered separately on the invoice line.