All I know is that the 9X20min was considerably easier to process than the 93X5min picture. I'll stick with 20min on objects like this.
Yes - if you can and there is no downside - you probably should. But I see you use HDR on objects like the Orion nebula. So - I assume you realize that "longer subs result in much better images" is not something you apply universally even to your own setup - let alone others with a range of f/ratios, read noise, and sky quality.
The point of the other thread is to provide quantitative guidelines that apply to anyone's setup, and the model used is the same one used by professionals. Both professionals and amateurs appreciate the benefit of stacking many subs, and realize that although the improvement from each added sub is less noticeable - it continues to improve the SNR.
Note that the other thread had a comparison of a narrow band shot using two different subexposures, and the end result showed little difference. Both that result and your result are consistent with predictions - assuming his exposure is sky limited and yours is read noise limited.
If you want to provide more insight into how your result is or is not consistent with the noise model - please provide data on your gain/read noise/sky background. You refer above to providing "raw" data to help people - but two independently processed images are not "raw" - and a general conclusion derived from them could in fact hurt people if they feel they need long sub exposures when they are sky limited.