In his article "Square Taper Bottom Bracket Interchangeability", Sheldon Brown wrote:

[Conversely,] if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length.

My question is: Is that "4.5mm farther in" overall, or "4.5mm farther in" per-side?

Specifics: A Sakae-Ringyo "SA" (road double) crankset requires a 122.5mm JIS/square-taper spindle; however, it seems they're rare as hen's-teeth for a 71mm Raleigh-threaded BB. But... a 132mm ISO/square-taper spindle (that will work with a 70mm BB shell) ought to work if the "4.5mm farther in" refers to each side of the spindle, where 132mm - (4.5mm x 2) = 123mm, which is close enough to 122.5mm.

Anyone know the answer? Is it 4.5mm overall, or per-side?