Pro Series allowed me to choose electronic funds withdrawal for Utah balance due. The electronic filing instructions showed that was the payment method. And, no errors showed on the return screens for Utah. 

Utah balances due can be paid online, by mail, or in person only. Nowhere on the TC-40 is there a place for the state of Utah to withdraw the funds.

Since my two clients ended up paying late once they realized that the withdrawals had not actually happened, they had to pay penalties and interest.