Some schools offer a distinct advantage for applying ED/EA. I think it is worth it to apply, even if you think you have a better score coming in DEC.
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There is no guarantee you will actually achieve a better score. If you delay your application waiting for something that never comes, and you apply later but at lesser RD odds, you have only harmed your chances.
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As long as your current score is in the ballpark, you probably will not be outright denied. The schools will probably defer the decision to RD rather than simply say “no”. Then, when your better score comes in, that will boost your chances at that time.
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Although most schools’ ED/EA deadline is before your test date, some will accept later scores before they make their final EA/ED decisions in mid January. Thus, you don’t lose anything by applying now and sending your Dec test scores to them at that time.
If you take those three facts into consideration, I think it makes sense to apply EA/ED with your current grades. At least to the schools at the top of your personal want list.