I wouldn't say there was anything particularly unusual about the positions of these pickups. The neck is perhaps a little further north than you would find on a Jazz bass. I suspect that this intended as a foil to the bridge pickup. You will note Jeff's old Dean signature model featured this slightly wider pickup spacing. Now, Jeff may not be known for using a neck pickup (his old P body/Jazz neck bass eventually had the neck pickup disconnected) but it makes for a usable bass for those who like to blend.
I very rarely use the neck pickup on anything these days (I think the record must be on my Pedulla Pentabuzz with a P/J. In over a year of owning it, I've probably had the P pickup on for less than five minutes). The Rithimic bridge pickup will quite surprise some Jazz lovers. It has a lot of guts, with a big presence and a lot of low midrange. It's substantially 'bigger' sounding than a singlecoil without losing any of the definition.