I recently took a job a large parts house chain and I've noticed a lot of the Castrol, Valvoline, Pennzoil etc..don't have the API starburst symbol on the higher viscosities like 10w-40, 20w-50. Is this a case of the companies not wanting to spend the extra money to get these "less frequently used" viscosities certified? I always suggested using API certified oils to my customers and I can't think of any modern vehicles(say 15 years old and newer) that spec anything higher than 5w-30.