It's a game, it's balanced for entertainment and.. Balance. Each extra ship was added through modding, and when you have a community bigger than a handful, setting a guideline for ship numbers is hard work (I don't think we even have something to say
"Right, this ship is agreed to be accurate to X hardpoint as a DN, so all DN's should be somewhere in this region" if you get what I mean.)
Lastly, it's initially made for balance, you'll find the basic ships are reasonably balanced to each other, even if it doesn't fit canon, because playability greatly outweighs the other. But as has been said, it's your install, if you feel the intrepid should be X values, then set them as much as you can within the confines of the outdated game engine. Nothing wrong with using some sources other than the show as has been said as well, but Voyager seemed less consistant than even old Galactica.
So you'll have a hard time finding the absolute correct values.