Surface Pro 2 - corner accuracy - pen input

My new Surface Pro 2 works like a charm, exept for corner accuracy for pen input. I know it's well known problem, but I couldn't find the satisfactory solution yet. Native calibration is making things even worse.

There's this 100-point calibration on various tech forums. Worth trying?

Any other solution? Anyone fixed it or just order a replacement unit?

PS: Tech support wasn't very helpful.