What you have there is , it will go to X1Y1 then bore a hole striaght down to -.5 then try to cut the circle (;-) You might want to add in 2 more params.

Param1 sets #550 with Setvar(550,Param1)
#551 gets set with Code"#551=[#550/2]"
From there everything is in place to cut the circle. I am using it and it works great.

as long as you can do full depth cuts in one pass(;-)

(;-) TP

OK, I see what you mean. I am cutting holes in a plastic box.
For multiple depths using this macro just feed down and call the macro as many times as needed.
I guess it wouldn't be to hard to modify the macro to increment Z down until #552 variable was reached and set #552 in the G-code.