As noted before, your pressures at cut-off are near perfect. Your OP said the cycling seemed fine, later it was "perfect". If you didn't change anything and it changed to long off - short on, you should find out why first. (Forget about air flow/duct work/etc for now.) If it has been long off - short on all along, I would suspect the orifice (restricted, not blocked) and since the high side is not going high and the cut-out pressure is correct, I would suspect the charge is low as well.
(If the cycling is OK when dead cold (has set overnight) then goes long off - short on, there is probably moisture in the system, freezing in the orifice...)
If the charge is low, the low side will not be replenished as fast as it needs to be. The pressure will drop causing the switch to turn the compressor off. It would cycle more than normal, short - short/medium. Add a blockage, short-long, high high side, negative low side (if you bypass the switch to force below 30 for a test). Add a restriction instead, short-long, high side pressure would depend on how low the charge was, same for low side. It may not go low/negative before the switch turns off, as your does not...
I agree it is time to look at the orifice...meanwhile recharging will eliminate a lot of guesswork...
EDIT:
WSManual N:09:01
R-12 Pressure Check.jpg