A thought on why there were Wagner and Griswold offices after the Griswold sale. I spent my working life with several large industrial companies, one of which bought the company I had worked for most of my career. Over the years I saw several large companies absorbed by the company I worked for and keeping the sales force intact, at least short term, which could be years, was always done. It is just too tough to keep the business channels, customer contacts, pricing agreements, etc, in place if you only have the acquiring company trying to do it and you throw away the all of the market insight from the company acquired. I would theorize that the sales, customer, market issues made keeping two structures in place the right thing to do.
Harry