This might not be the right answer - BUT - on G3 and G4, I thought I and K were offsets from where you were - therefore they will be a different position on every cut, because in your program they are all the same offset. They are not, as far as I know, the centre of rotation, which is what you seem to have programed them as.
I don't know, because I always use the "R" parameter with G3 and G4.