With new engines the pinch is always on a different spot. 1 micron difference can make 1mm difference in height of the pinch moment. When you get engines with selected parts then one of the things selected is a matching piston/sleeve with a starting pinch what it known as giving the best break in result. But because the production machines can not work precise on the micron so there are some spreaded tolerances giving different pinch moments.
Basically that is where the break-in is for to make the piston and sleeve match perfectly.

And why the taper if you may want to know.
When the engine is running the lower part of the sleeve stays cool due the fresh mixture but the upper part is hot due the combustion heat, so because the expansion by heat the sleeve will lose its taper getting straight.