It's not the same assumption. Target might not know theft has occurred at the time. It will show up later when doing inventory as a discrepancy and be recorded as shrinkage. Target in such a case has nothing to report to the police.

There may also be reasons not to report known cases of theft. Lack of evidence, uncooperative police and/or prosecutor, or small enough value so that the effort isn't worth it, for example.

The same assumption applies to all Target locations. There’s no reason for these locations to be any more underreported.

And again, Target has one of the most aggressive loss prevention departments in the entire first world.