No sure where you heard that from🙄. As far as I know the schools look at all DAT scores but mainly concentrate on the most recent. I am sure, however, that if you were to fall short of previous scores for a particular section of the DAT then that would certainly raise a red flag (by more than 1-2 points).
it actually varies, some schools take the most recent, others take the higher, and some take the average. there was a thread on this and someone posted a chart of all the schools and what each looks at. if i find it i'll link it.