The "Mathcad inputs" you are talking about are outputs, viewed from Mathcad, right? ;-)
I don't use Creo but maybe I can help you in getting your data into an Excel file.
You don't state if you are using Prime or real Mathad (15 or below), but as of the unit problem you report, I guess you are using MC15 or similar. Prime would support different units in an array - a plus of Prime among a lot of minus.
As Excel does not support units you would have to get rid of the units anyway if you write your data to an Excel file. You can do this by simply dividing the variable by the unit you want the value to be in when you collect your "inputs" into a matrix.
If you have further problems it may be helpful if you post your worksheet, if possible, and state what values you want to be written to which cells in the Excel sheet with WRITEEXCEL.