Exactly. The higher the piston travels through the shock, the thicker the damping gets. If you make the shock shaft longer, the piston starts from a higher initial position. This provides thicker damping through the entire range of compression because it also reaches a higher/tighter point on the triangle. I tend to think of this as fine tuning the oil without needing to take the shock apart. I think a good starting point for PSS shaft length is 9.6mm.

I don't recall who exactly told me about this, but I recall a teammate sharing this with me. Something they'd learned from talking to JJ Wang and/or his dad.