Why is a child object not rotating properly with parent?

The question:

Why is a child object accepting it's parent rotations when it itself is motionless, but seeming to refuse it when rotating itself?

The setup:

Assume 3 transforms in a hierarchy. (A) is the parent of (B), (B) is the parent of (C).

(A) has a script attached to it that controls movement of the collective. It has a section inside FixedUpdate() that translates input into rotation:

 //handle body yaw and tilt calculations
 float yawMag = rotationSpeed * Time.deltaTime * Input.GetAxis ("BodyYaw");
 //this actually rotates the main transform
 transform.Rotate (Vector3.up, yawMag);

There is also a section a little later that simulates inertia and tilts the transform a bit as yaw and speed increases.

 transform.localEulerAngles = new Vector3(0, transform.rotation.eulerAngles.y, balanceRotationLimitDegrees*balancerLoad);

(B) is a pivot for (C), which is the actual camera. (B) has a script with code in FixedUpdate() like this to handle and limit rotation:

 float trot = Input.GetAxis("Camera Traverse") * Time.deltaTime * traverseRate;
 transform.Rotate(transform.up, trot);
 float angleOffBow = Quaternion.Angle(transform.parent.rotation, transform.rotation);
 //Debug.Log("AoB: " + angleOffBow);
 if (angleOffBow > traverseLimit) {
     transform.Rotate(transform.up, -trot);
     Debug.Log("Bounced off traverse limiter");
 }
 
 float erot = Input.GetAxis ("Camera Elevation") * Time.deltaTime * elevationRate;
 childCamTransform.Rotate(Vector3.right, erot, Space.Self);
 angleOffBow = Quaternion.Angle(childCamTransform.rotation, transform.rotation);
 //Debug.Log("AoB: " + angleOffBow);
 if (angleOffBow > elevationLimit) {
     childCamTransform.Rotate(Vector3.right, -erot, Space.Self);
     Debug.Log("Bounced off elevation limiter");
 }

When running around and yawing (A), everything works as expected. The camera pivot (B) is appropriately rolled with the main body and comes back when (A) comes back to full vertical. The camera itself (C) also functions properly, yawing and elevating within its limits. When these two things combine, however, things go wrong. Rotating (B) while (A) is tilted results in some sort of permanent local Z axis rotation and (B) comes back up with its axes screwed up. I've tried a bunch of different iterations of different ways of rotating things and referring to axes, but I'm missing something fundamental here.

Any thoughts?

EDIT: Fixed it. Took the instances of

 transform.Rotate(transform.up, trot);

and changed them to

 transform.Rotate(Vector3.up, trot, Space.Self);

I was under the impression that these two things are essentially the same = the Vector3.up vector in self space is essentially the transform's up axis. Clearly I'm wrong here so, the question answer criteria is now "can someone tell me why/how these things aren't the same?"

Thanks!