Many people wish there vehicle only used a pint every 3 to 4,000 miles. That is barely considered burning oil, I wouldn't even worry about it, I wouldn't even think about high mileage oil at this point. Have you always used Castrol or just recently. Switching brands sometimes increases oil consumption for maybe the first couple of changes than everything returns back to normal. High Mileage oil is fine if you have valve seal issues, if oil is getting past your rings, then it won't do much good.