When you say you're driving it a lot less, do you mean after this oil sample was taken? Because this UOA was on a pace for almost 18000 miles a year (48.5 miles per day), which in my book is a lot. If it was my car, I'd keep it under 10k on the oil changes, even with a good TBN. An oxidation value would give you a better idea of oil life remaining, and if oxidation ended up looking good, then I'd reconsider going over 10k per oil change.