Water level offset only on Hummingbird?

I was looking at a feature on the Lakemaster Digital charts that I thought would be very handy. They call it Water level offset, which allows you to set the chart to the current water level. I have a few questions about this feature.

First question, As you change the water level, I suppose the footprint of the lake changes on the chart, and not just the depth contour lines? This would be very handy for the flood control lakes in north central mississippi. At summer pool, these lakes do not really resemble what they look like at spring or fall.

Second question.... Is this option available on any charts that are compatible witht he Lowrance brand? More exactly the Elite 7?

A few years ago that was a Humminbird-exclusive feature. I don't know if it still is or not.

Yes. Look on the BBC board for examples of this: LakeMaster Mapping Information Resource

No. This is a Humminbird only feature.