[phenixbb] phenix refinement question

Hi all, I have only started using PHENIX and have made an interesting observation. If I run my model through PHENIX refine (individual sites, individual ADPs, occupancies, optimized X-ray/stereochemistry weight, optimized X-ray/ADP weight options selected) I obtain R/Rfree 0.15/0.18 and very nice geometry values (data is to 1.7A). However, if I now take this refined model and run it through Refmac (without any refinement) I obtain R/Rfree of 0.19/0.21. Can anyone explain why is there such a big difference? Will this be an issue during PDB submission? Any and all comments are appreciated. Thank you all in advance Katarina M.