You asked for opinions ... and you have not received a serious one yet .... here's mine to consider.

The estimated values that authors list in catalogs are the OPINIONS of those authors.

Want different estimates ... publish a catalog under your name.

No matter what estimated value is given to most chips ... somebody will sell it for less.

Many chips that are purchased on ebay are often purchased by collectors/dealers (or "re-sellers") ... who have buyers for them at higher re-sale prices.