Howdy, welcome to GTM!
So this problem is sorta weird. Ironforge has different weightclasses than other mods. However, the game itself doesn't actually know this, so you have to keep up with it yourself. An Ironforge mediumweight is 200 kg (not counting weight from ballasts), and an Ironforge heavyweight is 400 kg (not counting weight from ballasts), so what you've got there is a HW. Whatever the game thinks it is doesn't matter. Sometimes, I like to name my bots "MW - [whatever]" or "HW - [whatever]" or whatever other weightclass to keep track.
(Does that make sense? I hope that makes sense.)