Traders are better off NOT using documents like LOI, ICPO, FCO, etc. Even if and when they rarely are used in internal trades, on a restricted level within specific industries, they have no legal or customary basis in International Trade whatsoever. In fact the presence of many of these terms are considered to be signs of Advance Fee Fraud, by knowledgeable players and law enforcement.
The Letter of Intent is not binding, and rather silly at the worst of times. An LOI by definition only registers intent to purchase, and it specifies this intent weakly, and due to its ambiguity should be avoided.