The current guidelines do not address how to enter past sales of error coins and to not enter sales of post mint “damaged” coins such as colorized ones. Obviously the major impact is artificially inflating the Numista generated value of regular coins. The guidelines should state that when entering sales of error coins they should not be attached to any specific year line.
Here are some posts discussing the problem:
Correct Numista value for UNC 2006 10 Sen Malaysia
If and when the guidelines are changed someone will need to read them to Mr. Robot.