Pass Labs Aleph Question - balanced vs unbalanced?

Ghostrider45 and Wloeb,
Thank you both for the explaining the design of Aleph amps. As an owner of Aleph 5, I've tried all three types connections: balanced, RCA w/ shorting pin, RCA w/o shorting pin, all from ML No. 39. My question is, from the circuit design point of view, what are the benifits or drawbacks of not connecting the shorting pin on the XLR input when operating throught the RCA input? On the other hand, does the input impedence change at the RCA input when the XLR shorting pin in inserted? Though this may not produce much effect as the 39 has pretty low(<50?) output impedence. Thanks.

Lightminer,
Indeed, with the manual in hand, I've been wondering more than once what Nelson Pass was hinted at when he said "...with...efficient speakers, you may find you prefer it this way". Prefering the extra volume range offered by the 6 dB difference, if one uses, say, horn speakers that simply blast out at lowest volume settings when pin 2/3 are shorted? I doubt. Sounds like a gain in quality instead of quantity. Maybe just ask Mr. Pass...Anyway, it's easier to ask questions than dragging out my Horowitz and pretend I am EE major. The 6 dB is easily adjusted by the No. 39 to compare the effect of shorting pin 2/3, and to tell the truth, just like you said, with the pin, it's more powerful. But it's accompanied by a little edge on transients, which might bring the perceived soundstage closer. Kind of like the passive/active difference in preamps.