Dear Gabriel,
yes you are right, there seems to be a problem with the generator. I need to investigate this further.
I made you another workflow using the Random Number Assigner Apache, which uses a library in the background. It will generate the numbers with the correct mean and std.deviation.
Sorry, I have to correct myself. Just thought about it and the problem is the min and max limitation. If you use this, you will afterards not get results from the full gaussian distribution but only from those inside the range. Hence, the mean and std.dev. of your result will change and reflect your true values. I would adapt the std.deviation, they were pretty high in some cases.
Best regards, Iris