A funnel is a population shrinking across ordered stages, and the number a reader wants is not the one the chart plots: it is the retention between adjacent stages. That is a ratio, and a listener cannot take a ratio by ear from two heights heard one at a time — so the pitch carries the retention and the counts are announced alongside it.
Left and Right move between stages. amCharts' pyramid and pictorial stacked series carry the same ordered stages and read the same way.