It's well-known that the RC4 keystream has significant biases that become less prominent later in the keystream. The most severe bias is in the second byte, which has a 128-1 bias towards zero. Other biases remain, and it's typically recommended to drop between 768 and 3072 bytes of the keystream.
Will dropping one more byte always reduce the bias, or is there a point when the bias is as low as it is going to get and it won't get lower as the keystream goes on? It doesn't matter if the bias is negligible.
Note that I am only talking about short-term biases, not long-term ones which RC4-dropN can't solve.
Does an N exist that results in minimum bias in RC4-dropN?