USPS Shipping Method

When regional rates are checked at the same time as the standard priority mail option it only uses the priority mail rate instead of choosing the cheapest rate from all three options. This has been a problem for years and needs to be fixed. There’s no reason this plugin shouldn’t be able to choose the cheapest rate from all priority mail options.
Another key point is that we do not want to confuse the customer by creating separate shipping methods for each of these as it because you would be offering different rates for the same level/speed of service from the same carrier.