Appending all worksheets in excel excel file into 1 master worksheet

I have created a workflow that looks like as shown in the image attached. What i find strange is that it works for 1 excel file but when I use the same workflow for another file then it runs the loop as it is supposed to but always gives the output from first worksheet only and doesnt show any records from 2nd worksheet onwards. Please help me find out what needs to be changed.