This may be true at your school, but you have no visibility into schools that have not required PTE. To the extent those schools exist, and to the extent their accepted candidates have not voluntarily elected PTE or CTE, there are an unknown number of invisible applicants potentially holding multiple acceptances. If this isn't true, what will happen to precipitate large scale WL movement anywhere to initiate the cascade of movement you are anticipating next month?
I am very new to this, and I am sure you have forgotten more than I will ever know about this process, but in the absence of people holding multiple acceptances, with all schools being at or above their target size (albeit with half PTE) common sense dictates that PTEs will convert to CTE when the time comes because there will be no WL movement without seats being created through the relinquishing of multiple acceptances. What else will create the need to initiate the WL movement?