Do we have to Spice duplicate data?

When joining 2 pre-existing datasets where at least 1 is spiced, the resulting 3rd dataset automatically defaults to be spiced also, with no apparent way of changing this. is this the expected behaviour?

The datasets are all from the same data source. This results in the data in the parent dataset that is spiced being also spiced in the child dataset, resulting in a double charge for this data.

If this is correct, are there any plans to change this, so that the customer only pays for the same data once?