I think you are definitely doing it the hard way. Have a single table and use one or more fields to code/categorize each time period/snapshot that you are trying to save. When you create a separate, new table each time, it's kind of the same effect as breaking normalization when designing a database. It seems like a good idea at the time, but the overhead and maintenance and extra crap you have to deal with whenever you program something to use the data is made harder each time, and managing all of those separate tables will become more than a chore.
