I have had a few experiences of being demo's 6922/E88CC Tubes, as a result of being loaned valves for a using for Tube Rolling sessions.
All Loaned Tubes were tested, and perfectly matched as pairs.
All loaned Tubes were ranging from a production era from early 1960's - mid 70's.
There were Brands on offer from Mainland Europe, UK and USA.
In my Phonostage and DAC the Amperex Bugle Boy (I recall Orange Print) was a no go for myself and others who were present, the intensity of the high frequencies was too much for the ears to settle with.
As conjecture only, a overwhelmingly Bass orientated presentation might just come out with these as a viable choice to add a noticeable impact on the balancing across the frequencies.
Other Tubes used as comparisons were much more of a 'what's your poison' experience.
My Phon's has selected for use, early 60's UK Tubes and the DAC has early 60's German Tubes as the selected type.