Another key point is that once the

Another key point is that once the gate is sealed additional second-stage time will not pack more plastic into the cavity. The extra time may impact dimensions but only in the same fashion as what increased cooling time would do. Extra second-stage time beyond what is required for gate seal (plus safety factor) is only wasting energy as the machine packs out the sprue and runner. If you find that increasing second-stage time past gate seal is impacting dimensions try to replace the extra time from second stage and add it to cooling time.