5.1DD is almost ALWAYS 448kbps.
My recent Little Mermaid restoration used the old DVD's audio (which according to sources is sonically identical to the laserdisc (and theater) release).
I couldn't understand why they had used 384kbps since, well, no-one uses 384kbps for 5.1.
That's a good reason, and even with the lower bitrate it still kicks the ass of that DEHT mix.