JOSM, USGS scanned Topo alignment

Hi,

I have tried to use the USGS scanned maps to edit Ni’ihau and Kauai - and found that they are mis-aligned by a mile or so. Any idea how that happened… and how to fix it? Ist it just Kauai+Ni’ihau?

http://www.openstreetmap.org/#map=12/21.9042/-160.1929

I found this - http://wiki.openstreetmap.org/wiki/Imagery_Offset_Database/Quick_Start

Would be a possible solution but for scanned maps I am thinking it would be better to figure out how the error got into the data and whether it was a systematic error because theoretically scanned maps should have very precise georeferencing…