For Oden, 18.6 might be a little low depending if he Roy can begin to learn to run the offense through him. But assuming the same 16.7/per36, that translates to 18.6 (probably more like 14-15ppg).
The 13.0 reb is accounting for Camby having some shared minutes with Greg out there and causing some diminishing returns on his 12.8 reb/per36 (which comes out to more like 14 reb/per40). Still think he'll be around 10-11 rpg.