Hi David,
it seems to me most of the info on Allied sub attacks in the site is extracted from Rohwer's "Allied Submarine attacks". Some of the data therein is controverted and some downright incorrect, so that any researcher with access to official files will probably find some discrepancies.
In Unbending's case there is also a credit for the sinking of Cosenza, which was lost on the other of the peninsula form where the sub was operating. Maybe the british had found a way of firing torpedoes in the Adriatic & hitting ships on the Tyrrhenian side....
I would definitely say the claim of Unbending sinking the Magliulo is incorrect, the target of that attack remains unidentified.
Ciao, Brian