Yes I prefer those slots over the others on plastic flanges.
If your installing over a wood floor I sometime drill a hole in plastic about and inch away on both sides of slot to secure flange to floor with brass wood screws.
But That is not always necessary( drilling the extra holes) but it is important that you screw the flange down to the floor.
If it is on a concrete slab make sure there is now upward flex of the closet bend.
You want the flange to hold the toilet down and not be able to flex upward.