With this setup your chainline will be 45mm, which is what Sugino specs for it now, even though you have to read a lot of fine print to actually find that out (link below). If your bottom bracket shell has not been faced, that will probably add a mm or so. Good on you for using a straight edge to actually check chainline, but keep in mind that most frames don't come from the factory lazer straight so even if you're right on on paper you might get a little bit of deviance when you actually measure front to back. The correct technical term for this deviance is "unspecified f***ness."

I'm not sure why they've done this, it's a real PITA. If you can return the cranks, I would do so, as this is a jingus setup that is never going to be quite right. If you can't, get a 2mm BB spacer and move to the inside, or if you're daring put the spacer under the cog.

This whole thing has left a big gap in the crank market, as the options are either cheaper stuff (bulletproof, RPM, etc...), more expensive overkill, random stuff that may or may not be any better than the cheapies (Pake, IRO), or tracking down the old RD-5000's that apparently work on the 103 BB (Soma has them for $100 with a 46t ring). You can also get the XD singlespeed, which is happy on easy to find 107 BB's, but is tough to find in anything but black -- allegedly you can get silver ones from J&B, but dealers don't seem to know about it. People complain about the XD being 110 and therefore having chainring flex, but that's a pretty flimsy complaint being that 110 compact doubles are now virtually the standard in road racing. Of course there's always the uber-uncool run it on a 107 with the chainring on the inside option, but even though I have no problem with doing it it just kind of rubs me the wrong way on what's sold as a track/SS crank.

http://www.suginoltd.co.jp/singlespeeder_e.html