Please help me understand Fortmax & Scorponok in IDW

I just finished reading Spotlight Ultra Magnus and Last Stand of the Wreckers. Why are Fortmax and Scorponok so relatively small?
In Spotlight Ultra Magnus, Scorponok was not that much larger than Ultra Magnus. I am disturbed by the ineffective pummeling that he gave Ultra Magnus. Scorponok should have used his huge claws to snip off Ultra Magnus's head, or used his shoulder cannons and other arsenal. Instead, Ultra Magnus gets the best of him with one shot in the face. Please, he's a city for pete-sake.
Similar situation with FortMax. He is tiny compared to his TV sized character. In the very beginning of the story, why didn't he just make himself very huge and crush everyone?
Is this all summed up in writer errors? Or is there some logic behind this?
In Spotlight Ultra Magnus, Scorponok was not that much larger than Ultra Magnus. I am disturbed by the ineffective pummeling that he gave Ultra Magnus. Scorponok should have used his huge claws to snip off Ultra Magnus's head, or used his shoulder cannons and other arsenal. Instead, Ultra Magnus gets the best of him with one shot in the face. Please, he's a city for pete-sake.
Similar situation with FortMax. He is tiny compared to his TV sized character. In the very beginning of the story, why didn't he just make himself very huge and crush everyone?
Is this all summed up in writer errors? Or is there some logic behind this?