We use SSA for our shipping templates with USPS Priority Mail as a shipping service. I noticed today (Veteran's Day) that USPS Priority Mail was used to calculate shipping timeframe for an order, but since USPS is closed on Veteran's Day and we selected this as an operating day for our business, we are not able to choose USPS Priority Mail from "Buy Shipping" options since it will not ship today but still make it to customer on time.

Is this a glitch in the system? Why would Amazon calculate shipping timeframe to use USPS Priority Mail but then not allow you to purchase the label in Buy Shipping options? Now we only have expedited options available (UPS 2nd Day, FedEx 2 Day) for Buy Shipping.