First appologies. I dont do FB, and am going to pretend it doesnt exist for the purposes of discussion.
OK, theres a few more clues here as to where you are coming from.
Good experiment and its great that you are thinking about this. But some background may clarify a few things.
First off, RMS really takes us back to a pre digital age. A signals level was expressed in terms of voltage, and RMS is a way of expressing an average voltage signal.
What it doesnt do is factor in the difference in perceived loudness across the frequency range. IE: the "Fletcher Munson" curve.
Human hearing responds differently to different frequencies. In other words, different frequencies sound louder than others. And this curve changes at different volumes. (IE: flattens out somewhat at higher volumes, contributing to the effect of louder seeming to sound better.) But I digress.
RMS "knows" nothing of this. It is totally ignorant as to the non-linearity of human hearing.
So what is missing from your experiment is: close your eyes. Which sounds are perceived
as louder? Despite measuring the same (or similar) RMS. Maybe its not obvious at first. I heard it. Even on a tablet! Its obvious to my ear.
Enter LU metering which IS designed to compensate for this.
But yet its still complex. And for every new detail learned, there are ten more mysteries revealed to explore.
Its one of the things that intrigues me so much about all of this stuff!