DP83869HM: Fiber register remapping from 0x0Cxx to 0x00xx

Section 9.6 in the data sheet mentions that the fiber registers get remapped from 0x0cxx to 0x00xx. It lists RGMII to 1000Base-X and RGMII to 100Base-FX. Does this also happen for RGMII to SGMII bridge mode?

I'm asking because I built a board with a DP83869 in RGMII to SGMII mode, I followed the direction set reg 0x1DF to 0x03 (RGMII to SGMII mode) then set 0x0C00 to 0x1140, then read 0x0C00 and it read 0x500 not 0x1140. I'm wondering if this remapping happens in RGMII to sGMII mode as well?

And in general about this re-mapping, exactly how does it work? When the re-mapping is in effect can you use either 00x0000 OR 0x0C00? If just 0x0000, what does 0x0C00 point to?

Thanks,

John S.