Two accounts ordered the identical $23 bubble tea cart on DoorDash. The one paying $9.99 a month for DashPass saved $1.46. And that account had Chase Sapphire Reserve perks stacked on top of the membership. Look closely at the receipts and you can see how the math is built. The non-member's delivery fee anchor is $0.99. The member's anchor for the same delivery is $2.99. The non-member's service fee is $3.45. The member's starts at $3.87 before the discount kicks in. Same cart, two different…