yep, i saw that also, just didn't want to spend the time changing it after i properly understood the arc command. it can be end point radius or also polar degrees with the arc center. though i'm not looking at my manual i thought it was GOl R n.nnnn or GOr R n.nnnn for the end point and radius and GOl A n.nnnn or GOr A n.nnnn for polar around a center point. but maybe l and r are for cutter comp only. the manual is written weird. mine says l/r for left/right are also used for cutter comp but the part of the 3000h manual i have says i/o for inside/outside
edit, actually it's unclear if it's supposed to be GO1 or GOl, page 11-10 in my manual here looks like a 1 in one instance and an l in another.
edit2: looks like l/r are only for cutter comp, can be ignored. i just didn't understand how they used a little note there. not sure if it's i/o for some machines and not others. i really don't use cutter comp, just pre process for the tool radius and if the tool doesn't produce the proper chamfers and radii then it's worn and should be replaced. i find it pointless for indexable tooling and not a great fix for badly ground tools since you probably aren't working with a true radius anyway.