Well, instead of doing something similar to superscript, you could actually use superscript. Though it may be simpler to just subscript the box, like so:
var psubox = '<f name = "Wingdings 2">' + '<z newsize = "18">' + "<subscript>*</subscript>" + '<f name = "Courier New">' + '<z newsize = "6">' + ' '+ ' ';
And you can modify the subscript ratio and offset in the Paragraph Globals dialog, or with attributes of a <p> tag, such as '<p br=false suboffset=30 subratio=200>'.
Though I would have taken a different approach to this completely, such as a table. If you make the table correctly, you don't need the Wingdings character for the box; that just becomes a table cell with an outline, and the cells with the text can have their vertical alignment set to middle.
Or, you could use a repeatable component, and make a separate graphic frame for the box, which again, can just be an empty square frame with a border.
Even if you want to do this all as regular text, without a table or a repeatable component or anything, you can still use an inline graphic for the box. And you could use <t> tags and set tab stops instead of all those ' ' entities.