The Public Service Commission hearings on Exelon's bid to buy Constellation Energy and Baltimore Gas & Electric started on Monday. The top draws -- Constellation CEO Mayo Shattuck and Exelon COO Chris Crane -- were also the leadoff act.

The hearings so far have contained no bombshells. But they shed new light on the proposed takeover, showing vividly how multibillion-dollar deals are about personalities and egos as much as about finances. We now know:

-- The merger would eliminate 600 jobs at the combined company, according to Wednesday testimony by Crane. Which jobs would be cut from Exelon and which from Constellation hasn't been decided. The companies have pledged to create jobs on net in Maryland, but that formula includes temporary construction jobs for building new facilities.

-- Offering Shattuck a big title with unspecified responsibilities in the combined company was seen by Exelon as part of the price it had to pay for Constellation. In prepared testimony Crane said that, according to Excelon CEO John Rowe, offering Shattuck the job of executive chairman in the combined company was "imperative" to get the deal done.

-- "Mayo would probably like to be CEO [of the combined company] but knows we will not pay a premium to give my chair away," Rowe told Crane in an email referred to in testimony on Tuesday. "Mayo would like to be 'executive chairman' for an undefined period."

-- Constellation's board asked Shattuck to ask Exelon if he could be CEO of the combined operation. "I said that was not a possibility," Shattuck testified.

-- Rowe and Exelon's board don't seem to have been crazy about the idea of Shattuck as executive chairman. However, Rowe wrote in an email, "with three-quarters of the board in our hands, I do think that the role of executive chairman might be tolerable..."

-- In 2008 when Constellation was veering toward bankruptcy, Constellation officials talked to Exelon about a potential bailout. "It was determined we felt that we might be able to put part of our lines of credit towards, to Constellation to help them through the situation," Crane said in testimony. They also talked about selling Constellation's nuclear plants to Exelon. (The talks came to nothing and Constellation was rescued by MidAmerican Energy and then by EDF Group.)

-- Even PSC Chairman Doug Nazarian, who is no stranger to lengthy examination of utility-company principals by hostile lawyers, seems to have been surprised by how long EDF Group lawyer Martin Flumenbaum grilled Crane and Shattuck. "Were you kidding about having a whole half-day for Mr. Shattuck?" Nazarian asked him late Monday. (He wasn't.)