The long and short of the story, is that the court, after scrutinizing not only the Memorandum, but also the wordings of the press releases and other documents that Getty Oil and Pennzoil had issued over the course of their dealings, found Getty Oil to be "in breach" of the Memorandum of Agreement _ the document the parties had viewed as a letter of intent. Thus, a document (the letter of intent) that the parties had started out viewing as non_binding and unenforceable, had changed from being that, to being a final agreement! Pennzoil, on the other hand, ended up with บǒ billion (later settled for ū billion) from Texaco for interfering in its deal with Getty Oil.
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.