A method and system for controlling the rate at which access terminals hand off from an IS-2000 (e.g., 1xRTT) communication system to an IS-856 (e.g., EVDO) communication system. A base station determines metric indicative of the rate at which hybrid access terminals hand off to the IS-2000 from the IS-856 system, and then based at least in part on the metric, dynamically adjusts a dormancy period that at least one hybrid access terminal must wait before entering a dormant mode in which is looks for service under IS-856. As the rate-metric indicates a higher or lower rate, the system may responsively adjust the dormancy period down or up. The rate at which hybrid access terminals operating under IS-2000 may seek service under IS-856 may thus be tuned to the rate at which they hand of form IS-856 to IS-2000.