mousemove() appears to be asynchronous

ERMMMM,,,

added a few lines:

MoveMouse(half_width, half_height)

Print half_width
Print half_height
Print MouseX()
Print MouseY()

given half_width is 200, and half_height is 150, surely debug output should be:

200
150
200
150

right? well...

Building AuroraSaver
Compiling:AuroraSaver.bmx
flat assembler version 1.52
3 passes, 4067 bytes.
Linking:AuroraSaver
Executing:AuroraSaver
200
150
0
0

Process complete

...any ideas?