How many steps are required to complete the given arrangement?

In the given Input-Output the numbers are arranged from both the ends simultaneously. In first step- Lowest number is arranged from the left end and highest number is arranged from the right end. In second step- 2nd lowest number is arranged from the left end and 2nd highest number is arranged from the right end and so on... Also while arranging the numbers, the numbers which are arranged from left end are replaced by the addition of the digits of that number whereas the numbers which are arranged from the right end are replaced by the difference of the digits of that number. Input: 76  14  12  96  86  34  65  45  56  24 Step I: 03  76  14  86  34  65  45  56  24 03 Step II: 05  03  76  34  65  45  56  24  03  02 Step III: 06  05  03  34  65  45  56  03  02 01 Step IV: 07  06  05  03  45  56  03  02  01  01 Step V: 09  07  06  05  03  03  02  01  01 01