I am replying in complete ignorance of the draft NSC paper.

The initial policy on reparations was quite harsh and was intended to penalize Japan. This policy, however, was not accepted by all American parties. The first group in the State Dept working on post-surrender policies was largely comprised of old Japan hands, including former ambassador Grew. They saw a postwar Japan as a bulwark in the Asia Pacific region; a strong Japanese economy would be in America's best interests.
This group was superseded by economists and others, some of whom deemed reparations and penalties as appropriate. This approach reached its peak with the Pauley commission, which called for shipping out most of Japan's machine tools. The initial reparations policy was largely ignored and delayed in Tokyo.
Several commissions visiting Japan to inspect economic and other developments gradually reduced the reparations quantities.

As Ellis Krauss notes, part of this shift was due to the reverse course. However, another thread that had been percolating along had an economic motive:
stimulating the Japanese economy in a policy called "crank up," pushed by the Draper commission. The economic and political motivations reinforced each other. (See Schonberger, H.B. (1989) Aftermath of War:
Americans and the Remaking of Japan, 1945-1952, Kent,
OH: Kent State University Press p. 163)

This shift may have partially motivated the revisions in the NSC paper.

Arthur Alexander