I should have mentioned this in the previous post, you are mixing apples and oranges... You do not need to get a SE commercial; you already have your commercial. This is different than a ME ATP with SE commercial privileges. You would however need to operate a complex single to commercial standards for the examination. Pilots can also pick from many CFI ratings for their initial; most pick either the F/W SE CFI, F/W ME CFI or Instrument Instructor as their initial.