I have a dual sim phone (535DS) with only one sim in it.Sim 2 slot is vacant.My data usage(Vodafone India ,not carrier locked) shows Sim 1 as 63.17 MB,and Sim 2 says 10.22 MB.and shows usage details for both Sim 1 and Sim 2.How is it possible ? My phone is on threshold .218 and working smoothly.When I was on 8.1 only Sim 1 data usage showed.