I've reread their statements and I'm certain they mean data series instead of data points. That is, there are 200 different types of data that they can collect

I've reread their statements and I'm certain they mean data series instead of data points. That is, there are 200 different types of data that they can collect from the logs (for as long as you have the storage to keep it), not that they can only store 20 seconds worth of data.