So let's sum things up: The LOI and similar documentary terms, are non standard, confusing, and lead to ambiguity. Documentary ambiguity is referred to in trade law as a condition "The Battle of the Forms" in which confusion from contradictory and ambiguous forms and documents damages the transaction. This should be avoided. To seasoned corporate traders and bankers, using terms like "Letter of Intent" is the mark of amateurs. What you properly want is an RFQ, request for quotation, from a seller or supplier. The seller may then reply to your RFQ with a quote OR full offer if they wish.
Moral of the story? If you're ever contemplating using a Letter of Intent in a business transaction, you had better watched out, it may not be as simple a matter as you might think. You better be very cautious, for it could result in unforeseen and unpredictable consequences!