Little savings add up quickly.The Manteca Unified School District board understands that all too well as the “budget crisis” starts its sixth year.A prime example is cutting back the time campuses open and close by a half hour before and a half hour after school. It saves an hour of compensation - and connected payroll costs - for a playground supervisor.There are a few parents - who for the most part understand what the district is up against - grumble about the fact they can’t drop their children off a half hour earlier than they did a few years back. They argue it is only saving a few dollars in reduced hours for the playground supervisors.But those few dollars multiplied by 175 instructional days by 30 campuses can add up.