For a permit imprint mailing, what is required of all pieces unless authorized otherwise by the USPS?

For a permit imprint mailing, the requirement that all pieces must be identical in weight is crucial because it allows for streamlined processing by the United States Postal Service (USPS). When all pieces are of the same weight, it simplifies the calculation of postage and ensures that the mailing is treated uniformly throughout its journey. This uniformity aids in efficient handling and can reduce the risk of delays or issues during transit.

Having identical weights is particularly important because it means that the cost of mailing can be accurately determined based on a single weight category, thereby minimizing complications associated with mixed-weight mailings. This requirement helps maintain consistency in postage charges and prevents any potential confusion or discrepancies that could arise from variations in weight.

The other factors, such as size, design, or postage amounts, do not carry the same level of impact on processing efficiency and cost as the weight does. Therefore, the emphasis on identical weight is a key requirement for successful permit imprint mailings.