It sounds like it's working perfectly.
You mount the tank high on the wall, and then when it's flushed, the water drops down with much force into the bowl.
In Seattle, many of these were installed to force the water out into the bay when the tides came in. High tank, which dropped with great force pushing the waste and water into the bay.
New toilets, where the tank is attached to the bowl, are called close coupled toilets. It's much easier to have a subtle flush when everything is so close.
In Levenworth, I saw a high tank toilet flush so hard the water almost spun out of the bowl.