I have just mailed 34 boxes to 8 units. During the processing of the Flat Rate Boxes, the postal employee mentioned there will be a new mailing box that can be used for military mailings that will be cheaper than the Flat Rate Box. Please check with the USPS if you are planning a large mailout to see when the new price will take effect. Also, I chose units, packed a box and kept a list of items in the box for filling out the customs form. During the time taken to pack the boxes, three units addresses were deleted. I chose other units with about the same number of soldiers and sent the boxes to those units. Since you can only request 2 addresses per day, you might hold off from sealing a box until you are sure that unit address is still available.