Mine ( RM800 ) goes click 1 quiet for practice, click 2 loud practice at home, click 3 loud enough for band practice with guitar and drums ( rock ) click 4 very loud band with Marshall stack and hard hitting drummer. Click 5 onwards never needed
Note for vol 1,2,3 I was using a single 210 cab, volume 4 both 210 cabs
It’s a loud amp but I guess most of its volume is at around 5 and the rest is a small increase.
My Orange Little Bass Thing 500w is similar I feel so it’s likely yours is faulty
You could always speak to Dave Green at Ashdown U.K. as very helpful