Strata picks its own direction for rotations of 180 degrees and will always go the opposite direction for rotations of more than 180 degrees. In other words, it takes the shortest path.
To control the direction of rotation, break it up into smaller rotational units, 120 or 90 degrees.
NOTE: Starting with Design 3D CX 6.1, you can also rotate 360 degrees very easily by using the new Rotate Script FX. The Script FX are found in the FX section of the Resource palette.