I have an image made up of multiple objects grouped together. Um, I guess they don't have to be grouped....but I still have to ask the question

Each object has a Blur of 3%. If I select 2 of them, the Blur changes to 2.2%. If I select 3 of them, the Blur changes to 1.7%. After I Group them, the Blur value is no longer indicated, which I'm pretty sure doen't mean there's no Blur. But before Grouping them, it seems the more objects I select, the lower their combined Blur.
Does this mean that the Blur is actually being reduced with each additional selection? Or is it some kind of anomaly?