RLE for DC/AC-coefficients separately for the blocks or at whole?

It is proper way - to code DC/AC-coefficients for all macro-blocks at whole?
I think that coding for DC/AC-coefficients for blocks separately gives lesser RLE-compression ratio.
It is right?

For example, at first we code DC-coefficients for all blocks. Compress they by RLE.
Then, AC(1) coefficients. Compress it by RLE.
And ... AC(63) coefficients for all blocks. Compress by RLE.
It is better for RLE-coding?