Upload a sample workbook. Too many moving parts to guess what's going on in there.
I'd want to see how the second data set is interacting here.
I've attached a small sample with the current calculations I have to the original post. I may have confused everyone a little bit describing a data set as different data sources, but a data sets that are within the same source. In the data source, you'll see groups of data by year, month, day, hour, and each data set has 20 rows separated by "Ranked Tile". If you slide the filters to include more data sets, you'll find "index" values become "null".
In addition, the calculation for "index" did not work for 1 data set, until I used the ATTR() function.
I figured it out! Some of my original calculations were wrong. All my calculations had to be aggregation calculations. Which actually meant that some of the computed values I had were in fact incorrect. "Actual Response Rate" was incorrectly calculated which i.e. [Actual Response]/([Cumulative Records]/[Ranked Tile]). It should have been an aggregation calculation where "Ranked Tile" wasn't suppose to sum, but stay the same value i.e. SUM([Actual Response])/(SUM([Cumulative Records]/ATTR([Ranked Tile])) which results with the correct value. Then I can use that aggregated value in the table calculation appropriately.
Sometimes the exercise of building the sample workbook helps us see things like this!