Trying to sum bank account number in RTF and pull the right 10 most fields of that summation

I am trying to create a RTF template for Bank of American CAD ACH payments and one of the fields in the file is bank account hash total. Which they are requiring us to sum all the payeee bank account numbers in the file and then take the 10 rightmost digits of the summation. I can get the summation to work properly however it pulls the 10 left most digits. SO i was thinking we would need to use a sub string to get the 10 most right digits. Below is the summation that i am using and also the