This was changed a long while ago because people like me were able to raise the ground to it's max height and then basically pick forward to extend it several times saving huge amounts of stone. This was never intended I don't think. You can still extend to save some rock buy raising ground from the side about 3/4 the way up.. Which is still reasonable. I have but stone wall around my base and tend to save all my stone from mining and other source now due to knowing how much stone is needed for stone blocks. I have two bases that have the equivalent of 90 2m Supports of wall that are 3m high. and didn't use an unreasonable amount of stone.

I'm in the process of building a single earthwork that will use about 120m of Stone earthwork minimum... and some landscaping inside. I haven't started yet but I would be surprised it too more than 1200-1500 stone which I believe I have laying around. It's already used 2000 plus wood. And will need another 1000 yet before I'm done.

So comparatively speaking the Earth works seems to be on par.