Just taking a SWAG here, but the 29/40 is 72.5% and was likely good enough to pass the morning. Somebody else had a 31/40, two Acceptable, a Needs Improvement, and an Unacceptable and didn't make it.
BELOW IS A COMPLETE GUESS AS TO HOW SCORING WORKS AND HAS NO BASIS IN THE WAY NCEES ACTUALLY SCORES
To quantify the afternoon lets say acceptable is worth 100 points, Needs Imp is 50 and Unacceptable is 0. Averaging all that together he would have 62.5% in the afternoon and added to his morning he would have averaged a 70% (provided the sections are equally weighted) and still didn't pass. So, I would say you probably can't have any Unacceptable OR you need at least 70% in the afternoon as well. This means you would need at least two Acceptables and two Needs Imp in the afternoon, so I'm guessing you were close.
I would say to work hard at the afternoon problems. The multiple choice section you can usually eliminate an answer or two, or "find" an answer somewhere in the code, and, if you miss one, not nearly the percentage of points as missing one portion of an afternoon problem. Also in the afternoon, it's quite obvious if you don't know how to solve a problem, not so much in the morning.