a Pentracer just advised me of a very good reason for removing sold prices. Sometimes collectors will sell pens at a greatly reduced price depending on their circumstances.
We have seen this on PenMarket where a seller announced he is liquidating and prices reflect almost half of market price. This happens to the best of us.
The logic of a seller to remove pricing or not show sold prices is really a courtesy to others so it does NOT reflect current market pricing.
I think that is very considerate of seller so others can maintain fair pricing for the pens they may list for sale.