When a junior officer (in charge of approval of a part of the system)decides the spec means something far beyond the scope of the previous junior officer who approved the original design (a near certainty since many officers rotate through assignments every 2 or 3 years), the project quickly collapses into a scramble to redesign and re-test. Since many of the project team members on the military side have no professional training, the comedy can be devastating, and can look like a Fawlty Towers episode.
RJSquirrel - you have MoD procurement in a nutshell there!