It is possible to control the behavior of the slope in the platform vectors by selecting the corresponding vector in the list and pressing the Edit button.

In the Platform Vector dialog you can use the Apply superelevations box, and by clicking the Conditions button you can decide whether the criterion should be the one set by the project superelevation table or is conditioned by the slope. In the latter case, a limit is established in percent, and it can be defined for slopes greater and less than said limit if you want to use a superelevation value equal to the slope or assign a specific value.