I got the 1M43S from the clock that runs in Mach3 when you hit the START button, so it mighit include the movement from X0,Y0, Z30 to the first point of the lead-in the moved to Z-4 the 6mm arc for the lead-in the cutting of hte job the 3mm overlap, the 6mm arc for the overlap, the move from Z-4 to Z30, the return and the rewind of the program..
Don't get me wrong I like the way you worked out hte 200mm/Min feed rate this might be a very usefull thing to remember for the futer especially when making small moves as apossed to long flowing arcs etc...