The armorer class doesn't differentiate from the regular 3rd gen guns and the smaller CS models with the flat-wound, really short recoil springs. Every 5 years or every 5,000 rounds is the recommended replacement interval.
However ...
I tend to err on the conservative side of maintenance and replace the springs in my own CS9 & CS45 about every couple of years or every 800-1,200+ rounds. In the CS9 it depends if I'm shooting a lot of +P and +P+ loads. (The issued loads used to be a major brand +P+ and are now +P.) I don't like +P loads in .45, so I seldom use them in the CS45.
Depends how much I'm shooting them, too. When I started having the guns field stripped for cleaning and the springs looked significantly shorter than new ones, I decided to simply replace them, and that was the approx round-count interval when I noticed a lot of difference in the recoil spring length ... and saw the empty cases being tossed farther.
On the other hand, I just watched one of our guys come through with a CS45 he claimed had the original springs. He said he'd bought it back when the model line was first introduced, too. He reportedly really only fired it for required qualification, so it's not like it was heavily used over the years. He completed the normal course-of-fire without any observed problems ... but I strongly recommended he replace the recoil & mag springs due to their age (which was quite a bit past the 5-year recommendation
).
The rather small & short single recoil springs in the smaller CS model guns take a bit of a beating, I'd think, especially when you consider the reduced mass slides and slide velocities of the little guns.
BTW, I sent you an email regarding the 4506 questions.