Flight Graphics Showing Take Off Distance Above Sea Level?

[ROBANAFI]

I've noticed on a few of my flight graphics that the take off height isn't 0m. This was taken on a lower level of a mountain and i probably was about 50m up.The only reason i got onto this was because i flew up a mountain and was quite surprised the drone went above the 150m limit but it definitely didnt get to 270m+(got to 220m). Even though i was at "220m height" because of the 1km distance and shape of the mountain i was only flying 40m above the terrain, i wonder if this is why i could reach that height?

Got myself a decent photo though(and video to come!)

https://flic.kr/p/2gjn5Mp