How to fix problems with outline created in Word from imported text?

I have a text file withe following data:
M1-Data
M2-Analyze
M3-Data Analysis-A,Y,2
M4-Add-A,Y,3,A
M4-By Changing Variable Cells-A,Y,3,B
M4-Change-A,Y,3,C
M4-Close-A,Y,3,O

I want to create the following outline from that data
1. Data
        1. 1 Analyze
               1.1.1 Data Analysis-A,Y,2
                        1.1.1.1 Add-A,Y,3,A
                        1.1.1.2 By Changing Variable Cells-A,Y,3,B
                        1.1.1.3 Change-A,Y,3,C
                        1.1.1.4 Close-A,Y,3,O

When I replace M2 with one tab, M3 with two tabs, M4 with three tabs; I get the following outline:
1.      Data
1.1.1.      Analyze
1.1.1.1.1.      Data Analysis-A,Y,2
1.1.1.1.1.1.1.      Add-A,Y,3,A
1.1.1.1.1.1.2.      By Changing Variable Cells-A,Y,3,B
1.1.1.1.1.1.3.      Change-A,Y,3,C
1.1.1.1.1.1.4.      Close-A,Y,3,O
1.1.1.1.1.1.11.      Options-A,Y,3,P
1.1.1.1.1.1.12.      Reset All-A,Y,3,R
Source-for-Outline.txt