"..Douglas' repeated assertion that stated military requirements for shipping were usually inflated."

U.S. Merchant Shipping and the British Import Crisis - army.mil - by Richard M. Leighton

"The whole massive shift of U.S. shipping into British services, decided upon during a crisis in the war at sea, was admittedly a gamble - one the U.S. military leaders naturally resisted, since their operations stood to lose if the gamble did not pay off. The gamble did pay off, and the dark predictions of the military shipping staffs did hot materialize. That they did not do so was, in some measure, a vindication of Douglas' repeated assertion that stated military requirements for shipping were usually inflated. During the spring shipping crisis of 1943, WSA often failed to meet these requirements as originally stated, but just as often ships sailed on Army account without full cargoes and on numerous occasions the Army reduced its requirements or even turned back ships for lack of ready cargo. What confounded the logistical experts above all, however, was the spectacular turn of the tide in the war at sea. Beginning in April a new and more effective organization of antisubmarine operations, bolstered by long-range bombers covering the mid-ocean gap, began to take effect. Ship losses in that month dipped to less than half those in March, and in June they fell to a point (182,000 deadweight tons) that by comparison with the whole experience since Pearl Harbor seemed trifling. New construction, meanwhile, continued to climb, in May and June making net gains over losses of more than 1.5 million tons a month in all types of merchant shipping. The military shipping staffs continued to shake their heads-the trend could not last. Early in May they still foresaw huge deficits, and as late as July the Combined Military Transportation Committee, analyzing monthly average losses during the first five months of the year, which had fallen well below the agreed planning factors, were suspicious as to the meaning of "the present lull in Axis submarine action."
The civilian shipping experts, for their part, had always been skeptical of predictions of shipping availability beyond six months in the future-approximately the length of the longest turnaround-and on the eve of the TRIDENT Conference Douglas and Salter sounded a general note of caution to the strategic planners:
All estimates of available shipping and requirements ... covering a long period extending into the future are necessarily unprecise and subject to all the changing fortunes of war. Shipping availabilities fluctuate with the progress of submarine warfare, routing, loss of shipping in assault operations, and a variety of additional factors. Military requirements vary in accordance with developments in the theaters of war and modified strategic plans.
For these reasons, Douglas and Salter were not too worried over the huge shipping deficits currently predicted by the military staffs, which, they thought, were "within the margin of error inherent in a forward projection" and "may well prove to be manageable." By the time the Allied leaders met again, at Quebec in August, the shipping deficits had in fact disappeared."