what is your thought on this?

A mistake made by one party is considered to be a unilateral mistake. This mistake in a contract is typically not given relief.

However, there are exceptions to this rule. If one side knows or should know that the other made a mistake, then they are not allowed to take advantage of it. A person who does not read a written document will not be offered any relief. In addition to that, relief will not be offered to one who neglected to review their own documents. Parties are permitted to correct their documents by the court in order to reflect their intentions.

Mutual mistakes:

A mutual mistake is a situation where both parties were wrong about the subject of a contract, and relief is often granted to both parties.

"Material effect on the agreed-to-exchange of performance" refers to a situation where both parties would be exchanging things significantly different in value from what they both intended to be exchanging. This is due to a mutual mistake.

"Party seeking relief does not bear the risk of the mistake" is a situation where negligence may cost millions. An example of this situation is if a shop owner sold an item for significantly less than what it is appraised for due to not knowing its true value. This item wholly belongs to the customer who bought it, and the party seeking relief is at a major loss.