I think if Mayo was involved, it may have been as I mentioned, that some tests are sent to Mayo because they have the ability to preform more complicated testing beyond what some local labs are able to do.

If there is no mutation causing the excess production of red blood cells then doctors look to potential other causes. Any condition which reduces the amount of oxygen available in the cells can cause your body to call for the production of more red blood cells (they carry oxygen) to supply more oxygen to the body. Conditions such as:
Congenital heart disease in adults,
COPD (chronic obstructive pulmonary disease) — the blanket term for a group of diseases that block airflow from the lungs — including emphysema.
Heart failure
Living at high altitudes.
Pulmonary fibrosis — a disease that happens when lung tissue becomes damaged and scarred.
Sleep apnea — a condition in which breathing stops and starts many times during sleep.
Nicotine dependence (smoking)
So your doctor may be on the right track with the consideration that your excess blood production is from smoking.

Have you talked with your doctor about your slow clotting time? Are they treating your PV with phlebotomies?