We're actually talking about Vader's TIE, which was a precursor to both of the TIE Advanceds you're talking about. I believe we'll be going with the round cockpit. I think the angular cockpit was a modeling design due to low polycounts at the time, which became commonplace. Remember that in TIE fighter the cockpit was round in cinamatics, but angular in game, which is probably where the discrepancy came about. All TIEs for the most part have Ball cockpits, therefore, so should the TIE Advanced, based on Vader's TIE. Once again, however, on the shiplist is mentioned Vader's TIE Advanced x1, not the TIE advanced from the games; a different design.