I have not talked about a free upgrade. In this case I am aware that there the OP wanted to use upgrade instruments. However, the best way to ensure flying in business class is to purchase business class with money. Then, there is a contractual obligation and if LH breaks it they have to refund 75% of the ticket value.

As I said before, I was upgraded twice on LH flights to PVG this year - for free and I have no status with LH. In both cases I travelled at time with high demand in Y and low demand for C. Anyhow, I never ask for upgrade and never count on it, so I can never be disappointed.

Well, I also agree with that statement.
It is not clear when the OP has flown and what the booking class was.
This determines whether how high the chance is that LH revenue mgmt. is approving upgrades with instruments.