Personal experience has been that Amazon delivery estimates and deliveries are extremely unreliable.
A one-day shipping ordeal could turn into a week. A two-day shipping will arrive past its "guaranteed" day for a solid 10-20% of all packages I get. And usually that guaranteed date will suddenly change on the day of. So you're expecting, and nothing gets there.
Basically, if you want to have a guaranteed delivery time on a package, do not use Amazon.