Why the difference in the two approaches?

The difference between the two approaches (O'Reilly vs Advance Auto Parts) is that Advance focuses on A, B, and C items, aiming for a quick return. They consider cost as well. One thing O'Reilly did very early on was to include their distribution cost in the store pricing. This makes it easier for them to implement incremental improvements, unlike Advance, which finds it difficult because their system is built around one DC delivery per week. When they increased this to two deliveries, which started around five to seven years ago for many stores, it was a significant hit to their P&L.