I request that the Step feature of SnagIt allow text values such as AA, AB, AC, etc.

I sometimes need to document for users the mapping of fields on a form with the corresponding location in an Excel file. See figure 1 below. However if there are more than 27 fields, SnagIt will not let me specify a column such as AB, AC, etc.  Instead it returns an error as shown in figure 2.

Figure 1


 
Figure 2