This model is highly heterogeneous. Perms from 0.5 -1000 mD. I suspect that they just wanted to leave the Cap Pressure "parameter" frozen, by using the usual escape route of assuming zero. Their focus is rel perms, hence all rock types are given one set of curves. Otherwise this would not be OK IMHO.

The capillary pressure if allowed to vary between rock types would be a factory in changing the trapped CO2 amounts. Here they want to leave this variation alone, and keep things simple.