My mom has a bank called Ithink financial. she has 2 savings accounts but all of the savings account number are the same. But each of them has s1 and s2 next to their account numbers. She wants to connect her account to a 3 party software to transfer money from a specific savings(s1) to another bank that she owns. How will she enter the account number when the softwares asked for it? Does she add the S1 to be specific or she excludes it ?