We need to see the pressures, ambient temp, and duct temp to make educated guesses..I agree that the capillary switch is probably the culprit if the charge is correct. tmm
I'm going by he claims he has determined that it's NOT cycling on low pressure. Seems to me this negates worrying about the charge for the moment, and he sounds as if he's electrically astute.
And by the way, I'm a guy who BELIEVES in guage manifolds and temp readings