Thanks Lars. As you suggested, we may end up having an input/filter to only display the data up to a certain point such as month end. I know most of the data has year/month, but I have to check if all of it does. Hopefully it is doable.
The snapshot table option would really be a pain in the neck, but I guess the best option if the first isn't doable.
Why did you say history tables is not the right choice? Is it because these two options are easier?