As stated on the title, I'm not sure if this was intended or not but

Level III Pipe

Level IV Pipe

This is expected behavior.

The mod does not apply a strict equal multiplier to every pipe tier. Captain of Industry uses an internal waypoint-based transport system, and pipes are also affected by transfer-per-tick limits. Because of that, higher-tier pipes can hit the same practical throughput ceiling after the speed boost.

So Pipe III and Pipe IV may both show/reach around 1800 throughput with the current implementation. It is not a UI bug — the displayed value is adjusted to match the actual in-game throughput as closely as possible.

I decided to keep it this way because it is stable and honest to the real game behavior, instead of showing inflated numbers that the pipe cannot actually deliver.

alright all good, just double checking.