Okay, that makes sense. The teambuilder took it as an Bulky Physical sweeper instead of a fast physical sweeper because of Roost. Fast sweepers tend to go all attack, while Roost is chosen on fat (or bulky) Pokemon. This is why it recommended 252 HP. Also regardless, the teambuilder's EV spreads aren't good always- you had wanted to go for the EV spread told in analysis or use your own. Hope this helps.