That is interesting and I am pleased for your result.
My experience is that every time I have tried exotic fuses I have heard zero difference in sound (or more accurately not enough that I could reliably put it down to the fuses). This has been with £450 SR fuses and with QSA fuses costing up to £1000 (although also trying their cheaper options as well). I have tried them in the 13A plugs and I have tried them in the mains inlets on the devices. Each time and wherever, zero difference or at least so small that I personally could attribute it to inaccurate audio memory between changing the fuses.
Mind you, I admit I am not a good candidate to try fuses because of a natural inclination not to comprehend how they can make any difference. If it was the bottle neck theory then a 5mm copper rod cut down to fuse length would sound best. One person I know on here has done that and suggest I at least try it.
I was under the impression was that some fuses such as QSA are not dealing with the fuse element as such but are rather dealing with ‘treatments’ to the fuse and this treatment can also be applied to many electrical components.
I say all of this knowing that many swear by the SQ improvements due to fuses but so far I am not one of them. Mind you my experiments have always been with borrowed fuses and I have not paid for them if that makes any difference.