I tried setting some products to 1 day fulfillment instead of 2 day.

June 1st Saturday night 7:46 pm an order comes in and buyer purchases an upgrade to Expedited Shipping for which I use USPS Priority Mail. I can fulfill the order immediately, 1 hour fulfillment, albeit the post office obviously won't ship until Monday the 3rd, but even then 2-3 USPS Priority mail results in delivery the 5th or 6th - probably the 6th since it is coast to coast.

Amazon, however, does not allow USPS Priority Shipping option saying a delivery date by Thursday the 6th can't be met.

Huh?

Since my Amazon hours are set to be closed on weekends 1 day fulfillment should be fulfillment by Tuesday the 4th since the order would not normally be seen until Monday.

***** Amazon's Expedited Shipping allows for 3 days shipping. ****

Even if shipping was on Monday the 3rd with zero day fulfillment the $8 USPS Priority Mail option with 2-3 day delivery should have been an available shipping option.

Ultimately I decided to buy shipping elsewhere. Then I set my products back from 1 to 2 day fulfillment.

Related: I don't want to hear any more about using Automated Handling Time and it setting fulfillment to 1 day. I turned it off. It doesn't allow for buyers to purchase an upgrade for Expedited Shipping with 1-3 day transit time.