Interestingly, "It Don't Matter to Me" seems to have the same melody as Joe Sample's "X Marks the Spot (Marie Laveau)", which was released in 2002 as part of The Pecan Tree.
Joe Sample had previously worked with Paul Anka, playing keyboards on Anka's 1976 album The Painter, while Bill Schnee, who co-produced "X Marks the Spot", is credited on Anka's 1998 album A Body of Work as an engineer and for mastering a track.
Makes me wonder if it was an old unreleased track that Anka later gave them, or if Anka recreated the backing inspired by Sample's track… or maybe it's just a big coincidence.