Of course it can result in less if something is found that requires the school to make the adjustment. If it's a mistake that you are getting a certain amount, it has to be corrected. I have seen it happen where actual amounts are reduced or increased after all information is received. If you are selected for verification, and information arises that affects the award, that can happen too.
In the JHU case, I believe that an award was made prior to the FAFSA numbers being taken into account. When the award was given, that was the total award the student was going to get. If any other money came on the table, the award would be reduced accordingly. So the bottom line of what the student had to pay was not increased. It just was not reduced when JHU saw that the student was PELL eligible. Only a few schools will let you keep PELL on top of their award Once the PELL eligibility is confirmed, that amount will usually reduce the amount the school is giving you with its own funds for need. They integrate with PELL and state awards as well as with outside scholarships. The need pool only gives out for what the bottom line need figure is, according to their methodology and is a figure computed from the family need number which remains constant.