This being Philadelphia, no elected official has ever seriously suggested that the change in property tax system would assure revenue neutrality — meaning the total amount gained from property taxes would remain somewhat steady year to year. But the millage rate is a tool that gives the mayor and City Council control over the amount of property taxes people have to pay — and it should be used. If assessments rise, millage rates should go down. But there has barely been a whisper about adjusting the rates either this year or last.