Collect and consolidate data

We have Office 2010 including Sharepoint 2010 deployed in our organization. Every month we collect a list of fixed assets from our subsidiaries using unstructured Excel worksheets. A user must go into each of these worksheets to run calculations on the data and consolidate the information. I would like to add structure to this process without making it more difficult for our subsidiaries. I thought about changing the worksheets to be more structured and then read out the data with programming, but using Office 2010 tools, what is the best solution to this problem? This is obviously a very common use case, but I've been out of the loop for five years doing Java web development. I'm assuming I should not have to do custom web development to streamline this process. One constraint is that we might not have Access Services or Form Services activated in our environment.