Search connections are not the same as download connections.

The number of hosts showing in the Connections tab are for searches, not downloads.

The number of hosts showing on a download in the Downloads pane of the Search tab are not the same ones that show in the connections pane.

You can disconnect all the ultrapeers in the connections tab and the downloads would still continue.

Leafs connect to Ultrapeers, because Ultrapeers handle the SEARCH traffic, not the download traffic.