Well I'm going to get scolded here.. But I owned a part store for 30years .
From 67 until 1995 . I had 2 AMMCO brake lathes . We turned a lot of rotors.
.. I'm going to say you don't know if they needed to be turned Until after you've made your 1st cut.
By then it's to late Heck JUST TURN THEM.
... NOW AS CRAZY AS THAT SOUNDS ... I DIDN'T BELIEVE the groves hurt anything . If the ROTOR WAS WARPED Then yes it needs to be turned. But after I was out of business I ran a set of ROTORS . FOR ABOUT 25k miles . With several large groves in them . But after putting a new set of Cheap pads on them .. After 25K MILE ON THEM THE rotors looked much better than when I PUT THE PADS ON THEM THE 1ST time.. so I put a 2nd set of cheap pads onto them & DROVE THAT SET OF ROTORS ANOTHER 25k+ miles.
... SO I'm not the Guy to tell ... SIR you have got to have these ROTORS TURNED..