Plot band does not have tooltip functionality by default, but it can be rendered quite easily using the Highcharts SVG Renderer tool.

In the chart.events.load callback function you can add functionality that will render a tooltip when hovering over the plot band using the chart.renderer.label method.

See this in action here: https://jsfiddle.net/BlackLabel/nk41ebvL/

You can read more about the power of the Highcharts SVG Renderer tool here.