Slightly Off Centre Culet

I can't speak to the light performance issue, but I can say that a slightly off center culet is not unusual with old cuts, and is very rarely bothersome or noticeable in person (obviously depends on the degree of off-centeredness). I've seen many jaw droppingly gorgeous antique diamonds with off center culets, so it's just a matter of how sensitive one is to symmetry. Off center culets are more common with OMC's/Cushions. Less so with OEC's/Transitionals.

Excellent news Erica! To me, symmetry, colour, and what not are only relevant if they effect they beauty of the stone and from the sound of it, it does not! I know some people are concern about re-sell value and so parameters become more important that visual beauty (diamond is NEVER an investment buy!). Gladly, I am not one of them. Thanks for that comment Erica!