impact of building shell price eleasticity despite ignoreShell

[robinhasse]

I noticed an interaction of price sensitivity for building shell and heating systems that I don't understand: I had low values for both sensitivity for construction but expected the building shell sensitivity to be irrelevant as ignoreShell = TRUE. But heating system choices remained evenly distributed, also for higher price sensitivity. Even extreme intangible cost on specific heating systems had no effect. I had to increase the price elasticity for the shell to very high values to get the expected behaviour.

This is strange because in literature I regularly find the condition that the price sensitivity hast be greater on lower levels of the MNL tree. But I've never checked that condition myself. The setup that works, violates the condition. While I don't see a problem when ignoring the shell (which actually means we effectively have a one-level tree), I'm irritated as I observe the same issue for irgnoreShell = FALSE. So far, I didn't manage get the expected behaviour with the full setup.

Maybe our hierarchical choice implementation is flawed?