To further elaborate, each list Capt and Fo is reset to zero each yeah on Jan 1st. When a trip pops up, scheduling goes in seniority order until someone picks up the phone and says yes. When that pilots completes the trip, the credit is added to their name and they drop to the bottom of the list for call priority. If they had 10 hours credit and someone else gets a call for 15 credit, they fall to the bottom under the first guy. Ostensibly this will give everyone an opportunity for premium time. But a lot of it also revolves around when they call, who answers the phone, who says yes, etc.