Cat calcium levels

My cat (5 years, male, neutered, ~7 pounds) showed mild elevated total calcium at his last blood test in late June, so a week later we did an ionized calcium panel, which verified very mild hypercalcemia (1.40 mmol/L). We scheduled an abdominal ultrasound for this past Tuesday, however, my cat ended up having an emergency literally one day prior on Monday (hairball lodged in intestines) and ended up having the ultrasound a day early. The ultrasound showed nothing that would explain the calcium elevation. They did put my cat under anesthesia to remove the hairball by massaging it up to his stomach.

At discharge today, they handed me paperwork from bloodwork performed at the emergency clinic, and his CA++ is now 1.63 mmol/L.

Obviously, he will need to have an xray to fully rule out anything that isn’t idiopathic hypercalcemia, but is a jump of .20 in a 3 week period crazy? The emergency vets did not seem very concerned about it, and his paperwork refers to it as “mild elevation” but I was too overwhelmed by discharge information to ask.

I just called the emergency vet to try to go over it further, but they have some critical patients and won’t get back to me until later tonight. I know the body has some funky responses to the stress of surgery - should I be worried?