It's absolutely not unusual that there's no half stop between f/22 and f/16; this was standard until recently, erm 1970s, or so, before microchip-nonsense and cheapo plastics were built even into expensive lenses. —— Roger Hicks could explain the reason why, do you have any of his books? I think it's explained in his book «A History of the 35mm Still Camera».
On Pentacon lenses from the 70's half steps are normal. They occur on my 50mm, 29mm and a 135mm I received yesterday from ebay, which has a half step between f22 and f16. The aperture rings on all three lenses have aperture indents that are a bit lighter than on many other makes and the slight stiffness of the ring on the 29mm sometimes gives the impression that its half-step going from f22 to f16 isn't there, going f16 to f22 slowly shows it is.