The Altitude scale and the VSI scale are totally unconnected- just next to each other. Obviously the altitude scale is evenly ruled, or linear. The VSI is logarithmically scaled- the first thousand feet per minute up or down covers the the same distance on the VSI scale as from 1000 to 4000 fpm up or down. You cannot juxtapose a scale like this against a linear scale like the altimeter tape- they are totally divorced from each other. Anyone who thinks they see a direct relationship must have been smoking something (apart from VSI reads up and altimeter reading increases!). I've been flying glass cockpit for 8 years! (737 and 747)