Ok i have my model Zbrushed and i want to export a displacement map to import it Into Maya

here is the problem i face

I set my Displacement options to
1.D32
2.channels : 3
3.Bits 16bits
4.Vertical Flips : yes
5.scale : off
6.Smooth: no
7.Seamless : no
8,9,10: Ch1,2,3 : full range
11:Ch1 res,2,3 : full

Then i increase the DbsubPix to 4 ( It's write that this is Map Quality , higher more details )

and when i get the map i get this :

This is level 4 of DbsubPix


On level 0 is this :



It's detail when i render with Maya on level 0 , but on level 4 it's nothing ??? whan i'm doing wrong ? ( the details on level 0 are not so good ...)I need more quality ...

Any ideas ?