What a pain.  Speaking as a former attorney, these situations piss me off.  English prose really isn't equipped to handle long conditions, exceptions and such.  What's important in a contract is that it unambiguously captures the intent of both parties.  Formulas, diagrams really should be used more often.  We're not on typewriters anymore - Word can handle graphics.  If you've ever seen a complex mathematical formula written out in legal prose, you'll know what I'm talking about.  End rant.