To me - ST is another 'store brand' based on specs - and it will always have contracts up for rebid etc - so this can be hard to chase. But again - it has to meet the specs in the bid tender ... also, some of the blenders buy products and they have bidders too - that have to meet specs ...
This is why API, ACEA, ILSAC, OEM specs (and of course BITOG) exist ...