There are lots of reasons one could raise the price.
None of those reasons can be shared since you provided no link to the subject property.
Since you improperly associated the 'assessed value' to the list price, I do not believe you will be receptive to any explanation regarding justification for raising the list price based on tangible or intangible assets.
Do a little digging in the Trulia archives regarding the sale of the home belonging to the owner of FSBO.
He hired a Realtor who raised the price and sold the home after he did all the FSBO stuff for over a year.
Again, there are many reasons. But for you, the first reality you must accept is what you see on aggregate websites is for entertainment purposes. If you are serous about a home purchase you need access to real data. Your local Realtor can give you access to the area MLS. There is where the real data resides. BUT, even the MLS is of no help if one is attempting to compare apples to oranges.
Annette Lawrence, Broker/Associate
Reamx Realtec Group
Palm Harbor, FL