Awesome solve Mark! A little more context for Addie:
The issue you’re running into stems from filters applying before the summarization happens, which means filtering out individual Pulse records changes the final averages. That’s why simply filtering for Pulse ≤ 3 removes rows you still need for the calculation.
Some Extra Fun:
Sometimes we use this create summary fields and then push them back down to the child table as a look-up field. This could be used to create rankings, or used to grab things like "latest child record" by using record ID. There are tons of cool use cases using this strategy.