Lets start with what is a Lockout stringing machine:
The lockout or "crank" machine will pull to the required or set tension and then lockout. (no more pulling)
"The stringer will then clamp the string in place"
The Constant Pull machine (drop weight or electronic tension head) pulls to the required tension and as the string naturally relaxes it keeps on pulling to the correct tension until there is no more relaxation.
"The stringer will then clamp the string in place"
The Lockout string tension will be lower than the tension that was required because the tension of the string will have relaxed (so if your required tension was set to 59Ibs then it will be about 56Ibs when clamped)
*note the tension difference is dependent on the type of string and the stringers technique
So the Constant Pull will always produce a "Firmer" string bed when compared to a Lockout machine.
This is why it is important to know which type of machine your racket is normally strung on, The stringer should ask this question when receiving a new customers racket.
I am lucky because I use a Wise tension head that can do both Constant Pull and Lockout tensions.
"In general there are two modes of stringing a racket: Constant Pull or Lockout. Your manual machine is designated a lockout style machine. When it reaches the set tension it stops, held by a disc brake. But we know the string stretches and results in a much lower final tension. Electronic machines continue to pull at the set tension until you clamp off. It’s all in the electronics. For a truly accurate and consistent string job electronics are the way to go."
So next time you get a restring with your normal string / normal tension, and the racket does not "feel" right it could be that it was restrung on a different type of Stringing Machine.
This video will help explain:
http://www.youtube.com/watch?v=3aYI5DXQxSA
Hope this helps!