I agree with you, Lisa. It's hard to give credit for blanks. I know there are times when it's difficult to obtain this information (dementia, unconsciousness) but in normal circumstances, I feel an effort needs to be made. PFSH and ROS aid in the building blocks of the level of the e/m.
The ROS obtained on a previous visit does not have to be re-recorded, but all new information must be documented along with a notation stating where the previous information is located in the chart. Also, a review of the PSFH obtained during a previous visit does not have to be re-recorded but, again, new information must be listed along with a notation regarding the location of the previous PFSH.
Some type of documentation is needed to record pertinent facts, findings and observations about a patient. The physician will be held accountable for his documentation and as stringent as carriers are becoming, it's in his/her best interest to supply this information; but this only my opinion.