Yes, the new norms are presumably more accurate, and significantly higher than the old ones.

I was just going to add that my children have been doing the MAP tests for 3 1/2 years now, and each of them had what I would consider an outlier decline at one point, and then the trend continued upwards.

I have read somewhere that once you hit the highest levels, the tests aren't incredibly accurate. So if there's a chance that this is a one-time aberration, I wouldn't worry much about the decline, plus, there may be reason to question the accuracy (whether higher or lower than you were expecting) when you are in the 99%+ range.

Just keep providing great reading materials, and I'm sure they'll continue to grow.