I m E + (highest level)
I had 2 complimentary upgrades (when flight was totally full) but one upgrade was when I had just joined the programme and hadn't any status.
I asked the desk that time why I was chosen that time.
As I had a dispute with TK when I wanted to enter the lounge with my LH Sen card but earn miles on M&S.
I was first told that this was not possible and only after a long discussion could I enter the lounge. when I got upgraded at the gate, I thought that this was for the inconvenience that it took them 30 minutes to decide I could enter the lounge while by that time it was already time to go to the gate
But it turned out that the flight was fully booked and I was the only person travelling single making it easiest to upgrade me to the single free biz class seat so status might not be the most important criteria to get an upgrade)