Newcomer / Intro Core mining question regarding yields

[Tyres O'Flaherty]

I placed my charges so, what it seems, was about optimum:

When the asteroid blew, I was given a message thus:

The question is, why did it exceed optimum despite saying it was actually optimim? I'm pretty sure there's something I haven't taken into account so would appreciate enlightenment!

I did seem to get a lot of chunks, about 20 once I'd blasted the bits stuck to the fractured rock.

 

[[VR] Orodruin]

Known visual bug.

 

[ChipStar65]

Yeah, ignore it. I've gotten top yield even with that warning. But, because there is an RNG factor in any core blast, it can sometime look as if the yield was reduced, to around 10 or so. On the other end of the scale I've had red top row squares aplenty before the blast and not gotten that warning, and the same range of yields, but usually reduced. Shoot for what your first pic shows and you won't go wrong in the long run.

 

[Tyres O'Flaherty]

Thanks guys!