Bfisk. I'd argue that crossing altitudes on an approach should be corrected too. How else will you get a good G/S check. To paint the picture again, imagine you are at a FAF which should indicate 1500 on that particular approach. On a cold day your altimeter may indicate 1600 there. If you've already done your math you expected this, but if you haven,t you may be confused and even suspect that your G/P indications are wrong.