Been thinking about this. I had a similar query which was answered very well here (in terms of how a fixed interval feed worked). So in one way you are right about nulls.
I think though, the writing of nulls to the feed by the engine as it realises there are gaps, and the sending of nulls to the process, may have different results. I’ve tried to work through the code and actually cannot reconcile what you are seeing in the feed, with what I think should be written (I think that an input null should result in the last value in the feed being written back to the feed). Without inserting some debug log code it is impossible to do any more (and I do not have a pulse counter).
You could check my theory by skipping incoming nulls…
I’m not sure if the screenshot above is showing the actual data feed values or interpolated values. There is a way of extracting just the values actually written to the feed in the link above to be sure.