Then you haven't been paying attention.
The AD-722x series are Lite-On based drives (MediaTek chipset), not NEC-chipset based Optiarcs. The AD-722x drives are based on the Lite-On iHAP322/iHAS322 (DH-22A8P/DH-22A8S)) and iHAP422/iHAS422 (DH-22A8H/DH-22A8L) drives. These drives are OK, but they are not the reason you choose the Optiarc name. They are not real Optiarc drives, but merely rebranded Lite-Ons. If you want a Lite-On, then just buy an actual Lite-On.
The AD-720x series drives are real Optiarc drives, based on an NEC-chipset. Those are the ones you want.