The proposed Southbury municipal budget is lower for the coming fiscal year than the plan currently in use.  The $21.6 million town budget has been approved by the Boards of Selectmen and Finance.  Southbury's portion of the Region 15 Board of Education budget is $49.8 million.  That spending plan is a 2.58 percent increase over the current year.  Residents will be voting on the $71.4 million on May 5th.