I was just positively trying to make the point that there is absolutely no correlation between the Altitude tape readings and the VSI indicator readings. I did not mean to cause you any offence, but to try and follow up a lead that there is a mysterious linkage between to two is barking up the wrong tree. If we examine your second diagram and graduate the red line into 500fpm divisions for each marker, it's easy to see when you try and correlate with the altitude scale that there is no way to do it. My apologies if my manner was abrupt- I'm like that- ask my ex-wife!