I appreciate the fact that you took the time to find some data and post it. That is cool and it is way more than a lot of people do in these threads. However, I will say that the 4" data doesn't make much sense when compared to the 3" data. The 4" flow rates should be 33% greater than the 3" flow rates. More than 33% if you take into account the edge effect.

Based on other numbers I've seen I think the 4" data in the table is wrong. A 14x4 filter should flow around 1200 cfm. Of course, flow depends on pressure drop so to be precise someone needs to say what pressure drop they are willing to live with and then measure flow at that drop. I don't know what K&N uses as a std pressure drop for filter testing but it is probably fairly low.