The VPOC isn't static. It's just the price with the most cumulative volume right now. As trades keep printing, a different price can accumulate enough volume to overtake the previous VPOC. When it does, the VPOC migrates to that new level.
This is the core event that VPOC Migration Pro is named for. Each migration is timestamped, given a direction marker (^ for up, v for down), and recorded in the session log. The old VPOC stays on the chart as a Naked level. The new VPOC takes its place as the current declared fair value.