Struggling With gCode Circles

When in doubt, find code to steal.  This Dutchmen (hence the unique spelling of circle) has a good explanation and subroutine.  I improved it slightly to add vertical and circular feed rates as parameters, but also to make sure I understood gCode suroutines:

%
( Mill a hole with the centre at x,y and diameter d, diameter of mill Md and depth z )
( Parameters:  x  y  d Md  z vfeed cfeed)
(             #1 #2 #3 #4 #5 #6    #7)
O100 sub
    #8 = [#3 - #4] ( Diameter of circle to mill )
    #8 = [#8 / 2]  ( Radius of circle to mill )
  
    G0 z 2 F #6
    G0 x [#1 - #8] y #2
    G1 z #5
    G0 F#7
    G17 G2 x [#1 - #8] y #2 i #8 j 0 z #5
O100 endsub
O100 call [2.75] [1.5] [1.5] [.5] [-.27] [5] [1]
(Clean up debris from circle)
O100 call [2.75] [1.5] [1.5] [.5] [-.27] [5] [20]
(remove inner circle )
G0 F 50 z 1
O100 call [2.75] [1.5] [1] [.5] [-.27] [5] [1]
(Clean up debris from circle)
O100 call [2.75] [1.5] [1] [.5] [-.27] [5] [20]
G0 F 50 z 1
%

Updated: No good reason to retract the cutting tool each time.