Made sure HeadPl3 and HeadPl4 for scenario's are only used when they actually contain a value. So from now on, when HeadPl3 (and/or HeadPl4) are NOT defined in the scenarios.csv, it stays nil. For the Design calculations, this means that the location.HeadPl3 is used when scenario.HeadPl3 = nil.
Related to Issue [
MWDAM-1406]