[TimeBalanceSpread] in WFP

I am setting up a WFP application in EPBCS and looking at an out of the box formula that uses [TimeBalanceSpread] - my understanding is the formula looks at the Account's Time Balance spreading property. None of the accounts in the member formula are using a Spreading Property. I don't see where this is defined in Workforce Planning.

Does anyone know where I can define the TimeBalanceSpread?

The member formula is -

"OWP_Expense amount"=(("OWP_Value")* [TimeBalanceSpread])*("OWP_FTE"->"No Property" - "OWP_Reconciled FTE"->"No Property")*"OWP_Partial Payment Factor"->"No Property";

Thanks for your help.