I remember a story about M&S in the U.K. Up until a few years ago they only sold their own brand food, which had a higher price and a higher perceived quality to other supermarket brands.

The story goes that their biscuits are made in the same factory and cooked in the same batch as other brands, but M&S required that their biscuits be taken from the centre of the tray where they were cooked in the oven more evenly.