(Time.CurrentMember, Measures.Sales) - 
(Time.CurrentMember.PrevMember, Measures.Sales)

(Time.CurrentMember, Measures.Sales) - 
(Time.PrevMember, Measures.Sales)

([Time], Sales) - ([Time].PrevMember, Sales)

Sales - ([Time].PrevMember, Sales)

(Time.CurrentMember, Measures.Sales) - (Time.CurrentMember.Lag(12), Measures.Sales)

(Time.CurrentMember, Measures.Sales) - (ParallelPeriod(Year,1,Time.CurrentMember), Measures.Sales)

Sum(YTD(Time.CurrentMember), Measures.Sales)