With student enrollment beginning to shift in south DeKalb County — as students transfer from struggling schools and home foreclosures displace families — county school officials expect to recommend changes soon that could shift millions of construction dollars away from the area. It's a move that could reignite old north/south rivalries. No formal announcement has been made. But by all indications, the changes would include not building a planned 31-classroom addition at Lithonia High School. The $11 million project was originally included on the system's construction priority list when voters reaffirmed a penny-on-the-dollar sales tax for school construction in 2007.