Just do your best with what you have. Records make it easy, but sometimes there are few records and sometimes there are none.
Be careful throwing stones, even if you are really confident in your support staff. There are mailing issues, objections between the parties and other things you may not know about.
I can tell you about once every few weeks I get a QME/AME report claiming they don't have records even though I have the cover letter serving them and the copies sure as hell aren't in MY office! It's really interesting when they review one set of records that were sent and the others were lost. (Sorry, I mean "never sent"). I just called a well known AME office this week and was first told that the second set of records sent were still not received. With a little prodding, I was then told that the records were located in another room where the receptionist had dumped them because she thought they weren't important. This happens all the time. Records get found when there are a few phone calls about it. Of course, by that point, the initial report is already issued.
I don't know why this is happening more and more but it is aggravating from this side as well. I suspect it happens more when QMEs ask that the records be sent to a different location than the eval. I can tell you the more suspicious bunch are convinced that QMEs do this so they can bill for a separate supplemental report after the records are found...