Yeah its really anoying if you reach the limit when the track is 90% done.
I do not know how to explain this in a proper way but im also afraid that, lets say a piece of wood, adds 10 points, but when you remove it it only deducts 8, like in the good old THPS days.
So if you add and remove, add and remove, add and remove, then there are some points

really cant come up with some better word for it) thats unused.
I tried my theory once by removing 3 barrels, but I could only add 2 before I ran out of "add more items to your sorry piece of track"-points.
Can someone confirm?