Oreos,
The 150 objects setting is the Epoch default recommended by the game developers. It is a bit quirky and the limit seems to have fuzzy boundaries. All bases on the server are built with it in effect as it has not changed since the server started. Players usually run into the limit when the build their base too "dense". If you use lots of small objects, such as sand bags and 1/3 walls etc, you are more likely to have problems. removing a few objects doesnt seem to have an immediate impact on the limit as i think it sort of averages the objects out or something.Always build with the largest pieces possible. One trick I personally use is that my bases never have a floor on the bottom, I always used the bare ground for that. You can move the pole around and sort of clip the area to build as well as stepping away and spawning the object, move back until it disappears and back up just enough to spawn it again and turn around with it a little closer etc. The white poles also seem to count as buildables as well.
Keep messing with it, you will get it to work, we have all been there.