The recent teams I've worked with get wrapped up in hours estimated for each Sprint, over analysis can cause team paralysis. Management wants to ensure each person on the team is at full capacity during a Sprint and want the estimates to match hours available. Unfortunately, it is a reality in most organization that projects are capitalized and the hours spent working on task need to be captured for business reasons. Therefore, they look at the initial estimates as gospel (i.e. in the Waterfall tradition). Until a development organization can show true benefits from loosely coupling task hours and capacity will this problem be resolved.

P.Parker