The only thing I agree with is: " RWIN is the most important setting realated to internet connection speed. Setting it too low can limit your throughput and setting too high could also reduce your connection speed."
When you use the term "Max Setting", this is a term I associate with "One Size Fits All".
To suggest an Rwin of 256960, which you've stated is a Max setting is clearly not suited for everyones individual computers and connections. This too high Rwin will cause lower download rates and can cause page lag. The optimum Rwin is an Rwin that is the lowest value that gives you consistant speeds. One size does not fit all. This Rwin your utility sets does not take into consideration average ping times/latency in the calculation. In fact, there is no calculation, just a Max setting.
One size fits all? No, it certainly does not. If I was a size 9 shoe, why would I want to wear a size "36"?