Last time I checked, certain information on AADSAS application can be updated (your bio for instance). But your grades, the schools you attended, LOR's, DAT score transcripts can't be changed - because they were submitted officially as original documents. Unless you update your new DAT scores or classes you repeated with better grades, which will be included with the previous grades and DAT scores.
The completed application you submitted will be the same application all the schools you chose can view. Whether you opted to add more schools later or not, it will still be the same original application the previous schools have accessed.