Sorry, Stu, dunno if I'm being excessively dim (it's been known) but - leaving aside the fact that you clearly intended to type A major rather than Ab major the second time i.e. F# C# G# - are you not just stating the bleedin' obvious when you say that to play a scale one semitone up (Ab to A) you must raise all the notes of that scale by one semitone?

I never thought of calling it anything like as fancy as 'Rule of 7' but remember quickly sussing as a small child that all you had to do was add or subtract 3 or 4 as necessary and safely ignore all that stuff called 'transposition' the music teacher was droning on about.