I have a Lockwood 530 cylinder which I pick quiet often, I find that sometimes after picking all the pins I might have to give all the pins a slight lift before it to open up, or sometimes a little more torque, personally I find Lockwood cylinders harder to pick than most other brands because of the small tolerances in the lock.
I have only been picking a few hours or so, hehe, so please be kind.
I have also been having trouble with this particular brand of pin tumbler lock (granted, it's the only lock I have ever tried to pick.)
I haven't found that it needs particularly much torque to get the pins set, but once they are all set, you need to start pushing at each of the pins again. You can be quite sloppy for this second 'pass', since the key pins are prevented from being pushed too far by the edge of the hull.
Why is this? I don't recall anything in MIT about this. (Mind you, I mainly remember the bit about "lockpicking is easy" hehe)
A bit more information about the lock:
1. Whether I turn it clockwise or anticlockwise the pins still set front to back.
2. I can easily pick it with up to the back four pins, but even when I've only got three in the front it becomes hit and miss for me. The front pin looks to be about a 1 (the others are all deeper.) I probably just need more practice, but the front two pins don't feel like they're setting; when it's just the back four they all do.
3. No security pins.
(4. Whinge: it's a pita to repin since you can't directly get at the driver pins and springs - you need to push them in one by one with a pair of tweezers while holding them in place with a plug follower.)
I don't know this is relevant or not, but I'm using an oblique hook. I really wanted to like the half diamond, but it just hasn't worked for me so far.