upperperc 95 doesn't give the average of the top 5%. It gives an estimate of where the top 5% starts. If the biggest numbers in the top 5% are much larger than the smallest numbers in the top 5%, then the overall average can be bigger than more than 95% of the numbers in the sample.
One simple example is where 96% of your numbers are almost the same, and you have a few numbers that are much much bigger. Then your average will be bigger than at least 96% of your numbers.