Most precancel devices were spaced to print on vertical definitives.
Thus to print correctly on the horizontal definitives (like your stamp), they were most often rotated and done as you see here reading up or down. This is quite normal.
Also, most precancels were applied at the local level with lesser degrees of consistency and quality control. Orientation "does matter" to the extreme specialist, but there is seldom any significant value difference.
Add: Here is a device from Alexandria, Indiana applied in three orientations.