Leerink analyst David Larsen views McKesson's earnings beat in Q4 as low quality since most of the upside came from a lower tax rate and lower share count. Excluding these two items, the company would have missed consensus by 4c, Larsen tells investors in a research note. While the initial FY18 earnings outlook looks good, management changed the definition of adjusted earnings, the analyst adds. The analyst believes the earnings outlook of $11.75-$12.45 would have been $1.30 lower had the definition not been changed. The business, however, appears to be stabilizing, Larsen adds. He keeps a Market Perform rating on McKesson with a $140 price target.