17 R4, 24 months in, battery lost 63% of its capacity

Hello everyone 

A lot of paranoia on this, I have. I once send my laptop for service to a local shop, for thermal paste and stuff. 

A few months later I noticed that the battery last much less than It used this. 

Today, it last about one hour and half (1h30). 4 months in and it was lasting 11 HOURS on battery eco mode + GTX 1080 disabled. I Might precise that the battery is the 99 mWh model and not the 60 something. 

I said I was paranoid earlier because I thought, at first, that the shop swapped out my battery and put something smaller instead. So they could keep my 99 mWh as a spare. 

But as HWINFO64 said, the 99 mWh is still here, but it just charges at 37% of its initial capacity. 

So that's it ? Barely 2 years in and my battery is good to trash ?

I know the lifespan of an average laptop battery, But this ISN'T an average laptop, even less an average battery.

Is that a known case ? What can I do ?

L've read that letting the battery discharge entirely to the point the that the laptop shutdown could restore battery life, is that true ? 

Let me know, peace