AVS fields are basic fraud control tools and help lower CNP transaction processing fees (see CNP transaction fee and AVS).
But keep in mind that there is an add cost associated with use of AVS => use these fields wisely.
If your transaction amounts are low enough, use of AVS can in fact result in much higher fees.
Estimate add cost associated with use of AVS vs. interchange fee savings with use of AVS.
Refer to your merchant account pricing or contact your merchant service provider to confirm your specific AVS add fee and your fee schedule to define your optimal processing logic.