Looks like a Fanuc controller - if that is the case and the G codes for canned operations is the same, you need an additional G71 instruction in the block immediately preceding the current G71 block, I believe it has a Q and a P variable (same variable names as the current code block you have, but the preceding block serves a different purpose). From memory (I am much more fluent with Okuma controllers), I believe the two preceding variables define the depth of cut per pass and how much stock to leave for a finish pass. Hope this helps!