This thread might be dead, but I came across this and thought I would post something rather interesting.
I have attempted this technique on several Master Locks #3 and the 500 series. I have yet to find a lock from Master Lock that this WON'T work on.
To ensure that the technique was being repeated as indicated, I placed my tension wrench in the top of the keyway in front of the key pin and put my lift pick to the very bottom of the key way. I then pushed the lifter pick in and lightly lifted it enough to count the pins to find the last pin without lifting the pins themselves. Once located, I performed the technique and the lock pops open. I have done this approximately 7 different locks.
Just thought you might be interested to know that it is possible to do it on more than the #3.