Well, there he goes again -- and so do we. In his first post-reelection press conference, asked about his plans for narrowing the deficit, President Reagan began talking about the Grace Commission's 2,478 ideas for making government work "more efficiently and economically."

We have a feeling that this is, in fact, the 2,478th time that the president has made this argument and also the 2,478th time that it has been pointed out that most of these alleged money-saving ideas are pure hokum.

The Grace Commission's report has been reviewed in detail by numerous respectable outfits -- including the Republican-led Congressional Budget Office and the perennially conservative General Accounting Office -- all of which have found that the claimed savings are either grossly inflated or require major and highly controversial and thus unlikely changes in popular programs.

The commission did identify some savings that could fairly be categorized as management improvements. The bulk of these, however, are aimed at the Pentagon whose budget is sacrosanct. Most of the other administrative improvements have either been rejected by OMB or, as the president himself notes, already adopted and the savings counted in tallying up the still huge deficit.

The Grace Commission's biggest money-saving ideas, however, have nothing to do with running a tighter federal ship. They are benefit cuts, pure and simple. For example, a major source of savings is the commission's pious hope -- no plan for its realization is provided -- that the rate of growth in Medicare benefits could be limited to growth in the gross national product. With more elderly people and ever-improving medical technology, this could mean sizable cuts in benefits. Other savings would come from another big round of cuts in food stamps. Still more would come from sharp cuts in federal pensions -- although these wouldn't even be realized until the next century.

The budget deficit is, after all, so big -- and the total size of the domestic budget (other than Social Security and Medicare) is so small relatively -- that no imaginable administrative savings could make a dent in the deficit. Only big-dollar cuts in program benefits will do that. But those are numbers the president would rather ignore as long as he can talk vaguely about those 2,478 ideas instead.