Yeah, it doesn't quite work the way that expert says. Information that gets to the towers ends up elsewhere in the phone system as records in enormous databases. When law enforcement want to know ping information, or even just the last ping, the phone provider doesn't send something to the tower but rather the provider just runs a query against their database and they have the answer rather quickly. If it worked in a way where it was dependent on asking a tower "Hey, have you seen this phone?" the provider would have to make requests to tens of thousands of towers. This would be hugely inefficient and require a cell tower to be more than, well, a cell tower.
The same is true of a cell tower dump. The phone provider doesn't request the tower to dump whatever data it has. As I said above that information is already stored in a database elsewhere. And all the provider does is query all records associated with that tower within a given time frame.
That expert's expertise either only goes so far or he is intentionally being misleading.