The Public Company Accounting Oversight Board found 123 audit deficiencies related to fair-value estimates and asset impairments in 2010, making asset valuation the most common audit problem. Market volatility always makes it tough to value assets fairly based on market prices.  But that doesn’t mean management forecasts—and the assumptions and methodologies of financial modeling used in corporate pricing—couldn’t benefit from additional scrutiny. Emily Chasan reports at the Wall Street Journal’s CFO Report blog: The Big Number:  123   That’s the number of audit deficiencies related to asset-valuation problems found among clients of the Big Four accounting firms in 2010. Market volatility…