I am confused by some of your statements. Do you choose to drive 10 mph all the time like a snow plow or(haven't read entire thread)? Also when was the last time you have seen modern engine oil destroy an engine due to deposits? There are plenty of people running very extended oil changes with oil analysis done and zero problems. We don't use paraffin, graphite or other deposit prone materials in our oil anymore. Hell dino oil can be left for a year and 5-7k plus on several engines for 300+k miles just fine including lots of idle time, short trips etc. like a police car, ambulance, cab. Dark oil is not necessarily dirty oil, you should do yourself a favor and jump on Bob is the oil guy and do some reading there is a ton of good oil education on there