Ah, okay, this does make sense now. So standard deviations are 68% confidence level, but drawing an ellipsoid using those values would "degrade" my confidence level to about 20%? So I need to scale it for about 4.21 (or some close value I got in my project) in order to be at 95%.

I've mixed up confidence level of a single standard deviation with confidence level of an ellipsoid.

Thanks