Some while back in one of my know it all moods I described the differences between Early, Mid, and Late model Tigers Unfortunately for me David Byden saw my learned discourse and pointed out that the term "MID" is one that modellers and model makers use rather than the factory

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There is a distinctive "Early" Tiger and an equally distinctive "Late" Tiger but the "Mid" merely represents the changeover on the production line from one to the other so that you will see Tigers that appear early but have late wheels and vice versa.
It just means in wartime if you have a batch of Wheels or exhausts or whatever left over you do not waste them you fit them, thereby producing a "BITSA".
This means you can intergrate your late parts with the early type Tiger and still be right although I would expect that the "SS" Battalions were equipped with either Early or Late and no mongrels as they always got the best equipment but I am only guessing at that.
shaun