Please help with calculation

[Dragon of the void]

I have a problem with the calculation of spaceyard-output and the various factors that influence it:

Let's asume I have several boni on my homeworld:
(rc) racial characteristic
(rb) racial bonus
(pb) population bonus
(hb) happiness bonus
(em) emergency build bonus

So they do not calculate:
2000 * rc * rb * pb * hb * em

And they do not calculate
2000 *(rc+rb+pb+hb+em)

The closest to what is displayed in the game is
2000 *(hb+rb) *(rc+pb+em)

Well, but I am a little bit lost as to why this is so ??

Or is this a problem with my Version only ? (gold with some mods, none affecting production as far as I can tell)