It would explain it, if we didn't already have information on when OT ships were designed and introduced. Like I said, Vader himself is still flying a Eta-2 Actis' at this time. You would expect him to have the best fighter he could get. They could have designed a new fighter to sit inbetween the Eta-2 and TIE advanced v1 in the main villain fighter timeline, blending the two designs together to further show the evolution. They went the lazy canon breaking route instead, probably just so they could reuse an existing 3D model.