Ok that makes sense. I think this comes down to the cya built into cure temps/reten times. Also, I replaced both the belt motor and speed controller on our sprint HO so it may or may not have re-calibrated, not sure on that. We basically run at 1:30 retension and adjust the dryer temp if needed throughout the day so we're curing wb/dc/hsa fully but not over baking the plastisol, there's an ideal for each ink and then a happy middle ground to keep from toggling the dryer all day and scheduling each shift to death to match up ink types.
Remember that a typical ray gun is reading a cone of air with the cone's base centered around the laser dot, we honestly don't use them but a couple times a year anymore. I always thought they read high like Alan says compared to an atkins probe.