As one of my mentors said, "It's not about you knowing the proficiency 100% when you pass, it's about knowing it 100% when you're teaching it to others."

I wasn't 100% when I turned mine in, but they passed me anyway - after many hours of studying and working with others, they knew I KNEW it, but just froze up a bit during the official presentation.

I'd had some extenuating circumstances (wife passing away, etc) and was running up against the time limit to prove MM prof (otherwise we would have had to file papers with GL to ask for an extension, etc). I was told "We KNOW you know it, we're going to pass you, but promise me you'll get at least a C certificate when you can." The certifications are basically the Masonic equivalent of "teacher certifications" that prove you know the work 100% backwards and forwards.

In Texas, none of the work is ever written down (its all by word of mouth). At least in my Lodge, nobody ever gets to the "sit in Lodge to prove proficiency" stage without spending hours and hours working with others and the Deacons have already unofficially "passed" you - the sitting in Lodge for it is just a formality at that point.