The REAL VALUE of house is determined when a WILLING and ABLE buyer puts up the money to buy it:
Until that happens; everything you hear is just OPINION; some may be well-founded opinions, but they are opinions none-the-less.
When a SELLER refuses to use a Realtor; they are saying that their OPINION is the only one that counts. That is exactly why some FSBOs will sit there for a year or more.
The Banks use APPRAISALS to protect their interests.
Buyers use Realtor's CMA to protect their interests.
You might be able to pay too little, if the Seller does not know what they are doing:
What do you think the chances are?