Developers in particular like to know what spot on the charts their app got to. By not filtering the results everyone has a definitive view of the placement of these apps.
So they should filter the top list like you mention, but show a definitive list online.
This could be provided as a separate option on iTunes connect. If it was purely to cater for developers it doesn't need to be in the main app store interface.
So they should filter the top list like you mention, but show a definitive list online.