I think what happened is that some people perceive they go upwards even when going flat. I discovered that after I once tried to stop at the top of a hill but already was beyond the top because the car started to roll down by itself. Perhaps you could adjust some angles of view?

I think you're probably right. The camera's pitch exactly matches the car's pitch, so I'll fiddle with having it maybe only take 50% from it.

that's what I tried, it always rolls back and I went clearly long time uphill and at best only flat, but clearly never went downhill to make up for same elevation as I gained to be back at same level with sea where I end up no matter how long I go uphill