PCIE Qsys design flow issue

Hi Dears,

I design pice project according user guide, when i set parameters of pcie as UG i will get a error as below:

"Error: pcie_hard_ip_0.pcie_internal_hip: Stratix IV GX and Arria II GZ do not support a non-maximum RX buffer credit allocation"

So i can only change the setting to "Maximum" as attached file shows.

Could this be only a DOC debug?!