The Multiples of Pre-Tax Profit That Berkshire Paid for Marman and Iskart in 2013

The multiple of pre-tax profit that Berkshire paid for minority interests of Marman and Iskart in 2013 were considerably higher than the multiple's Berkshire paid for earlier purchases. Can you please explain why the valuation formulas changed, why the multiples weren't fixed for future increases in Berkshire's stake? Charlie Munger: "We do that because Warren wants to make it eccentrically difficult for himself"