Found out my grocery delivery fee was hiding a 31% markup this whole time

I was comparing my last 6 receipts from the delivery app against the store's weekly flyer prices, and it hit me that I wasnt just paying the $9.95 delivery fee plus tip. Some items like cereal and canned soup were priced way above shelf price, like a $3.29 box of granola bars ringing up at $4.31. That's a 31% markup on top of the fee, and nobody tells you that at checkout. I even called customer service and they confirmed the app sets its own prices per item, not the store. So I started doing pickup instead, which is free, and I save about $14 a trip on 3 or 4 staples alone. Has anyone else caught this sneaky gap between delivery apps and in-store pricing, or am I the last one to notice this scam?