I think what he/she is saying is that 71st percentile means 71% score LOWER than a 5.0. A 5.5 is 87th percentile, so 16% of test-takers score exactly a 5.0. If you assume that a given 5.0 scorer is in the middle of the 5.0 pack, then essentially a 5.0 is equivalent to the 79th percentile (71 + 16/2).