It is very clear that Debragh is not looking at 'raw' test scores. It is clear that some scaling has bene applied. the raw test scores might have been integers between 0 and 60. Each of these scores is 'mapped' to a new scale that goes up to 100. The mapping is not linear.It may be that a 60 maps to a 100, a 59 maps to a 99, a 58 maps to a 98, and a 57 maps to a 96. That would produce the gaps. the raw test scores would not produce a bell curve either. If it a a multiple choice test, the low end will be skewed by random guessing. It is also possible that differnet school district encourage different groups of students to take certain tests. Very often, raw scores are mapped to a bell curve, raw test scores sledom look anythnig like a bell curve. Think about that. If you are takng the ACT, the differencve between a 36 and a 35 might be missing a single question. However, the difference between a 21 and a 20 might be missing 2 or 3 questiosn.
Uless you can some that they scaling was applied unfairly, that some student's tests scores were adjusteed up and other were not, there is really no indication that there was any wrong doing.