Yep. My understanding is that the strictness of penalties has almost no bearing on the murder rate. Most murders are either crimes of passion, or committed with the assumption the perp will never being caught. Murderers aren't thinking - "Hm, 20 years of prison I could handle but 25 years is too much. I suppose I won't murder my wife when I find her in bed with another man."
Increasing the penalties for murder is an extremely ineffective way to reduce the murder rate.
I used to believe in this, but SF proved it wrong. Simplify writing up or catch-and-release has caused the city's crime rate to go through the roof.