Thanks for the note - I never knew. I'll have to remeasure my chainline, but with Formula fixed/fixed hub and previously a Surly cog (just changed it after is was sharktoothed at 12k mi) it was definitely not 4.5mm off. Maybe 2mm at worst. (I know the math doesn't make this possible) Runs smooth and noise free and after 8k miles no uneven wear on sides of Sugino75 48t chainring.
Al