Ok, lets see some of these cases then...
If there are questions on your application then the VO usually asks for additional information and/or documents. Judging by the other posts on this page, it sounds like they are running a little bit behind schedule.
Sometimes you see no updates on your application after 2 or 3 months so what are the GCMS notes going to tell you.
In my opinion (because this is just my opinion and there is no right or wrong way in doing this) 5 months is fine to order them. Definately order them if your application goes over 6 months.