I would not pay to much attention to the frame ends, you circled in red. They will not be visible, when the cab is fitted, so it is much more important your parts fit the small part on each frame, which is labeled “D3” in the Trumpeter drawing. And to me it seems, like your printed fit very precisely there.
Also, as Gino (HeavyArty) states, the frame length is often peculiar to each variant. I simply copied the frame size from the Italeri parts, when I lengthened the frame parts on my M985.