You could also look at this in another way when the information we have is incomplete...
How much of the WW2 gold plunder ended up in the hands of the US? Gold was plundered by both the Germans and Japanese. Could the US have taken such gold and kept its existence secret and only disclosing in official announcements gold holdings legitimately acquired? How large could this "unrecorded" holding be? This would explain all the Swiss refining going on and US exports of gold while the fort knox and other gold holdings remains static. However it does not explain why its taking so long to return German gold, unless the refiners are working too slow to produce enough "new" bars that no longer contain nazi or Asian markings on them...
