PickedY doesn't return a Distance. It returns a Coordinate. Probably the top level entity of a 3ds is diffrent from the top level entity in the .X File. You should try the following:
a=loadmesh("test.3ds")
print entityx(a)
print entityy(a)
print entityz(a)
b=loadmesh("test.x")
print entityx(b)
print entityy(b)
print entityz(b)
Everything should be Zero. If it's not, then you know the reason for this strange behaviour. You could then check the Hierarchy of the meshes and compare the 2 formats.
a=loadmesh("test.3ds")
print entityx(a)
print entityy(a)
print entityz(a)
b=loadmesh("test.x")
print entityx(b)
print entityy(b)
print entityz(b)
Everything should be Zero. If it's not, then you know the reason for this strange behaviour. You could then check the Hierarchy of the meshes and compare the 2 formats.