2.1.1612 Part 1 Section 21.3.2.25, to (Ending Anchor Point)

a.   The standard does not include restrictions regarding the relative size of 'from x' and 'from y' with respect to 'to x' and 'to y'.

Office places additional restrictions on the relative size of 'from x' and 'from y’ as follows:

The left side (from x) should be less than or equal to the right side (to x).

The top side (from y) should be less than or equal to the bottom side (to y).

If these restrictions are not met, Office uses the values described in the 2D transform (xfrm), if they are valid. If these values are not valid, Office does not render the shape.