Wonder what kind of severance package comes after less than six months? Time Inc. Chief Executive Jack Griffin is leaving after less than half a year on the job, the company announced in a memo Thursday. In the statement, Time Warner Chief Executive Jeff Bewkes said Griffin’s “leadership style and approach did not mesh with Time Inc. and Time Warner.” Griffin, whose selection as Time’s chief had stunned many, immediately began reorganizing the staff when he arrived in August. Griffin had previously been the head of the magazine division at Meredith, a Des Moines-based publisher of Better Homes and Gardens, Ladies Home Journal and others. Bewkes said in the memo that Time Inc. will be headed by an interim management committee until a permanent successor is named.