Whatever the District nets from its imminent tax amnesty period isn’t free money — not all of it, anyway. The fiscal 2010 budget included $20 million that officials estimated the “tax compliance initiative” would generate. But the success of recent amnesties elsewhere suggests D.C. will raise more, if not significantly more, during the two month program. The city is owed about $200 million. There are no guarantees, of course. It was CFO Natwar Gandhi who estimated a $2.50 cigarette tax, up from $2, would generate an additional $9.7 million this fiscal year. Instead, collections through May were down $5.4 million compared to FY 2009.