For a while I tried my Earthworks hypers Z30XL running into my R4, with simple Y splits to the Tmod and Vmod channels. I noticed that it didn't sound quite as sweet when I ran that way as when I ran into just one. It reduced the low end, and on those things the last thing you wanted was more bass rolloff. I've done it with other mics and it didn't seem to make much difference. So, I think Chris is right... sometimes it matters, I can't tell you which mics are more fussy about it than others. We tend to say "if the plug fits it must be good", but that's not always so. You ever notice those higher end studio pre's with the adjustable impedance? I don't think that's just a gimmick, I think matching impedance can matter... which is probably the cause for a lot of the anecdotal opinions of "these mics sound sweet with this pre".
In Bean's case... try it using cheap Y splits, use the phantom from the LB if it's always on, and turn off the power on the SD. If it works great, so be it. If it seems sub-optimal, chalk it up to experience and try something else.