The Invoice Match Option and Match Approval Level are independent options. You can perform whichever Invoice Match Option you want regardless of the Match Approval Level.
Invoice Match Option:
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Purchase Order: Payable must match the invoice to the purchase order
Receipt: Payable must match the invoice to the receipt.
Match Approval Level:
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Two-way: Purchase Order and Invoice quantities must match within tolerance before the corresponding invoice can be paid.
Three-way: Purchase Order, Receipt and Invoice quantities must match within tolerance before the corresponding invoice can be paid.
Four-way: Purchase Order, Receipt, Accepted and Invoice quantities must match within tolerance before the corresponding invoice can be paid.
Invoice Match Option:
-----------------------
Purchase Order: Payable must match the invoice to the purchase order
Receipt: Payable must match the invoice to the receipt.
Match Approval Level:
-----------------------
Two-way: Purchase Order and Invoice quantities must match within tolerance before the corresponding invoice can be paid.
Three-way: Purchase Order, Receipt and Invoice quantities must match within tolerance before the corresponding invoice can be paid.
Four-way: Purchase Order, Receipt, Accepted and Invoice quantities must match within tolerance before the corresponding invoice can be paid.