I stumbled upon something I found a bit odd. I have 4-child tables of which one has a grandchild table (Years).
All the child tables all refer to the grandchild table for calculations. Initially I made multiple table occurrences of the grandchild table (Years) and linked them to each of the individual child tables. By mistake, I referred to the original grandchild table in one of the other child table's instead of the occurrence, for a calculation. The calculation worked fine. I then deleted all the grandchild table occurrences and all the child tables calculations still worked fine - just relating back to the one grandchild table (Years). I'm surprised this works. Any explanation for this? Is it because they all link back to the parent table? Note that the relationship between the child table and grandchild do not allow the creation of deletion of any records.