They do, for the most part

As you read through the three different accounts you look for inconsistencies. You've learnt over time that no two witnesses are going to agree on all the details, particularly when they involve the committing of a crime, but the basic facts in this case are as follows.

1. The two Mathewson sisters decided to welcome Mr. Carter with a spray-painted reminder about his age and alcoholism (?). You note that the older of the two, Grace, takes full responsibility for the prank and even goes so far as to explain that she had to talk her younger sister into coming with her.
2. Mr. Carter caught the girls red-handed and kept them from getting away, by (depending on the version) sitting them on, pushing them onto, or throwing them onto his bed.
3. Mr. Carter told the sisters to clean up the messages sprayed onto his bedroom wall.
4. The girls used their shirts to try to clean the wall. (Here the versions differ as Sally and Grace both claim that Mr. Carter **** them to remove their shirts so he could see their naked tits, while he implied that that decision was made by the students.)
5. The sisters could not clean the mess and Mr. Carter told them to put their shirts back on. (Again in Carter's version it sounded like that was almost immediately after the girls took their shirts off, in Grace's he pretty much used them as a strip show for a good five minutes.)

The accounts differ again at the end. Sally Mathewson included a detailed account of her sister offering first a hand job and then a blow job in an attempt to keep Sally out of trouble. Neither Grace nor Mr. Carter seemed to recollect any of that conversation in their narratives.

The vandalism part of this is pretty straight forward. According to the very outdated Code of Conduct, damage to school property amounting to more than $100 was a level 3 offence. In addition to the paddling the students parents would be notified and the cost of repairs would be added to the tuition for the semester. You referenced the disciplinary code in the back of the book and noted that a level 3 offence merited a dozen blows on bare skin.

A footnote at the bottom of the page indicated that all paddlings must be conducted with at least one witness, and that the aggrieved party could (at the Dean's discretion) administer some or all of the punishment.

Mr. Carter's decision to have the girls remove their shirts was another matter altogether and one that would have to be dealt with by Ms. Naylor.