The official casualty number from PLA is the least important thing to India. It's like cutting your finger off to show someone that you are serious, yet they don't care. India has a zillion ways to spin PLA's number, why is that important?
The thinking of helping Modi save face and deescalate is very piece meal fashion and does harm to the long term stability of the border. China should think in broader, longer term, not just how to get out of the current crisis.
The idea of help Modi de-escalate is dangerous. It underestimate India society's ability to form public opinion based on the interest THEY see. It underestimates India military's appetite to take casualties. A few dozen casualties, a private humiliation, means nothing to them. Last year they had fighter jets shot down, pilot captured, helicopter crashed, but nothing changed. Why this time is any different?
On the contrary, China's goodwill can only been seen as a sign of weakness,i.e. China is eager to deescalate. If I'm Modi, I would draw the conclusion that China is afraid of economic backlash.
And that might not be too far from the truth either, that Chinese leadership is afraid of economic backlash. Otherwise, why not disclose the casualty number which every normal country in the world would do, which means nothing to India!
Knowing the thinking of your opponent is really important. If you have been dealing with someone and things don't work, change it instead of keep repeating the same failed approach again and again.