Valvoline does not market their synthetics for 10, 15 or 25K OCIs. I don't believe they ever have. Instead they fall back on telling you to follow your owners manual. I know many VOAs have shown that their oils can go the distance. But if you have a car for instance that recommends a 7500 mile or 10000 mile OCI, would you not feel just a little better knowing they state that it will go that fsr?