USPS Simple Shipping chose First Class Letter for order

I had an order over the weekend where the customer ordered 2, hard plastic eyeglasses cases. They show dimensions as 7x4x4 and a weight of 0.4. These, obviously, need to go into a box for shipping, but the plugin returned a first class mail rate of $3.56 for the order. This is a first class letter rate, not a parcel rate.

How do I tell the plugin that items with sizes of 7 x 4 x 4 do not fit in a first class letter classification? I had to cancel the order and ask the customer to resubmit because we auth the card before we ship so that we NEVER store a customers card number on the site. Hopefully, this customer will place the order again, but the shipping is likely to be twice what the letter rate was.

In the WooCommerce shipping, the configuration for the plugin had the First Class Letter and the First Class Parcel checked as well as both the First Class Package service options.

I am a bit befuddled as to how the plugin decides which rate applies to an order.