Hi Socks,
School records are changed, added, deleted, manipulated, and lied about, and there is not a darn thing you can do about it...except you may ask for them specifically if you are lucky enough to know what is missing.
Things you can do to help yourself:
Ask for all records at one time. I'll try to dig out my letter I used. I got it from an attorney website and it was wonderful. It covered everything.
Take a scanner or phone to take scans photos right then. Often if you ask for them later, the docs suddenly disappear.
If you need more time, write a note (ask them for a copy right then) documenting your request for more time.
Count the number of pages that are in each notebook/file. Document the number of pages so you can see what is missing.
Write down summaries of discrepancies, issues, and events that you find inconsistent or outstanding. Mark them with sticky notes.
Note the handwriting style of individuals so you can recognize it on other notes to make sure the same person really did write the note. Often staff will add handwritten notes later to help cover for their mistakes/lies, but it is sometimes not the same person they claim wrote it.
Reschedule as many visits as it takes to document EVERYTHING. If something is missing, then ask for it in writing while you are there (and ask for a copy of your note.)