Interval
Use this field to specify the amount of time, in seconds, that the system is to wait before proceeding to the next action.
To construct a value for this field using an expression, click the button to the left of this field.
The contents of this field must use this syntax:
numericExpr
where numericExpr is a number or an expression that resolves to a numeric value.
When you click Event Actions form, the system "wraps" this content within an INTERVAL( ) parameter, which yields this final syntax:
to return to theINTERVAL( numericExpr )