This probably goes way beyond the scope of what is intended for this software, but it seems to me that this could be a good platform for the measurement of drainage.
I have looked hard for a software package which can measure drainage. The only example I have found is MasterBill. I got a demo of the software; the drainage package looks good but unfortunately it is only sold as a add-on to the main measurement software (which is expensive).
Once all the proposed levels have been applied in Kubla Cubed, manholes could be plotted with invert levels/depths for each one and drain runs could be plotted between the manholes. This could produce a schedule of the length of drain runs in different depth categories and produce a spreadsheet in line with SMM7 or NRM2 measurement practices.