I think it could be Baba was mistaken or, as has happened to me a few times, it is also possible Baba was dialling OP at the same time and the line from OP connected while Baba was still dialling. Baba was so sure he phoned first and he seemed as honest as the day is long so that I am at least glad nobody appears to be calling him a liar as well, except Roux of course, because I just don't think he was.
I'm guessing any record of the calls from the buggy's mobile, where Baba had called from, have all poofed and we all know OP's 0020 cell disappeared for weeks into the defense's custody before it was made known to the prosecution and disclosed so you can be sure the defense had it "checked" it out by then. Hmm, perhaps evidence of that call is also in those recovered files from the 3rd cell phone that Nell made sure the Judge knew how to reference?