[Table Q] shows the final result, which is that the average total cost of dealing with postal packets is as follows:—
| For an ordinary letter— | d. |
| Under 1 ounce | .382 |
| Over 1 ounce, under 4 ounces | .747 |
| Over 4 ounces | 1.404 |
| For an average letter packet | .457 |
| For a postcard | .353 |
| For a halfpenny packet | .432 |
| For a newspaper packet | 1.063 |
| For a parcel | 7.091 |
For the letter packets under 1 ounce in weight, for those between 1 ounce and 4 ounces in weight, for the halfpenny packets and for the postcards, the estimated average cost will be approximately the actual cost per packet; but in the case of letter packets over 4 ounces in weight and newspaper packets, the variations in weight and convenience of handling are considerable, and there will be an appreciable variation
for individual packets above and below the estimated average cost. The cost will vary with the weight and size (but not proportionately), and the deviation will be greatest in the case of the heavier packets, since with both these classes the average weight of the great bulk of the packets is less than the general average. Of all letter packets, postcards, halfpenny packets and newspapers, the number exceeding 4 ounces in weight forms less than 10 per cent. With so small a proportion of heavy packets the result may be taken as almost exact in the case of the lighter packets. It is not in excess of the actual cost, because the calculation, taken as a whole, is biassed in favour of the heavier packets.
The resultant figures are figures of average cost. They represent the cost of those packets in each class in respect of which the average amount of service is performed, and not exceptional cases, as when packets travel over very long distances, or when a packet is redirected or returned to the sender, in which latter cases obviously double the normal service is performed.
The calculation is approximate in that at certain points it has been necessary to frame estimates on imperfect data. This is inevitable in dealing with a service conducted over a large area and under diverse conditions.[624] In general the manner in which the result is affected by the use of imperfect data has been indicated. These variations have been borne in mind throughout, and, as their effects are produced in varying directions, the combined effect is not such as to invalidate the results arrived at.
The result suggests the following conclusions:—
(1) That no class of packet sent at the letter rate of postage involves a loss to revenue;
(2) That there is a large profit on ordinary light letters;
(3) That in the case of packets of the weight of about 4 ounces the profit is less, but is still appreciable;