The old extended time used a method "determineDate" which would essentially return the date from the published exam if a null date was entered during delivery.
Something like this will need to be replicated in the new extended time (with some additional text that says leaving any field blank will result in it using the default).
Currently it looks like any nulls will default just be returned as nulls. For example leaving a null "start date" for an exception will allow the excepted to student to start before the actual start date.
The ideal I think would be if the methods could return it directly, but it would have to have a way to also return the null value in case of editing it in the UI too. . . Though maybe returning the "default dates" for this UI isn't bad of an idea either. Having them blank (null) or having them return the default values seem about the same solution? Maybe we need different methods like "getEffectiveDueDate" ?