I tried to create a list of new parents in NXT based on the filter of 'as of' a specific date, and found that the 'as of' field is functioning as a 'this is the code on this particular date' instead of a 'starts on this date' like the constituency code 'from' field in database view.  You really need to make the 'as of' a selection of operators including Starts On to give more flexibility in the filters.