First answer and it’s the correct one.
I still disagree personally.
If you drove a long distance would you measure the height of every hill along the way as part of the distance travelled? No. Distance (or length) is a one dimensional measurement.
Accurate measurements are with a straight ruler or taught tape measure, measuring the curve is embellishing.
The depth which you penetrate will not change if you have an 8” curved dick or an 8” straight dick.
I say all this with a curve that costs me about half an inch.