ColorMatrix Saturation and OpenCV Saturation result are different

Question

Below is the C# Logic for changing saturation of image. Referred from here

Note: We are using this saturation matrix

     R   G   B   A   W
 R  [sr+s sr  sr  0   0]
 G  [ sg sg+s sg  0   0]
 B  [ sb  sb sb+s 0   0]
 A  [ 0   0   0   1   0]
 W  [ 0   0   0   0   1]


s  = saturation

sr = (1 - s) * lumR 
sg = (1 - s) * lumG 
sb = (1 - s) * lumB

lumR = 0.3086  or  0.2125 
lumG = 0.6094  or  0.7154 
lumB = 0.0820  or  0.0721

Below is the basic snippet of code from c#.

            saturation = 0.1 //sample value
            float sr = (1 - saturation) * lumR;
            float sb = (1 - saturation) * lumG;
            float sg = (1 - saturation) * lumB;

            float[][] ptsArray = {
                                 new float[] {sr + saturation,  sr,  sr,  0, 0},
                                 new float[] {sg, sg + saturation,  sg,  0, 0},
                                 new float[] {sb,  sb,  sb + saturation,  0, 0},
                                 new float[] {0,  0,  0,  1, 0},
                                 new float[] {0, 0, 0, 0, 1}
                             };
            // Create ColorMatrix
            ColorMatrix clrMatrix = new ColorMatrix(ptsArray);

            // Create ImageAttributes
            ImageAttributes imgAttribs = new ImageAttributes();

            // Set color matrix   
            imgAttribs.SetColorMatrix(clrMatrix,
                ColorMatrixFlag.Default,
               ColorAdjustType.Bitmap);

Below is code from Python with OpenCV

import cv2
import numpy as np


img = cv2.imread('faceimg.jpg')
imghsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV).astype("float32")

saturation = imghsv[:, :, 1].mean()
print("orginal",saturation)

(h, s, v) = cv2.split(imghsv)
print(cv2.split(imghsv))
s = s*0.1
s = np.clip(s,0,255)
imghsv = cv2.merge([h,s,v])
saturation = imghsv[:, :, 1].mean()
print("after change", saturation)

Checked the result image using OpenCV and C#. Output from C# is more darker in color as compare to python's output when saturation value is 0.1

ColorMatrix approch is high performant and it's easy to implement as our main logic is in C# only.

Question: How to get output as OpenCV-python's saturation output from C#'s color matrix approch