Question about warning 68 in NONMEM

Hi, I have two questions about warning 68: (WARNING 68) THE INTEGER FUNCTION IS BEING USED OUTSIDE OF A SIMULATION BLOCK. IF THE INTEGER VALUE AFFECTS THE VALUE OF THE OBJECTIVE FUNCTION, THEN AN ERROR WILL PROBABLY OCCUR. First question: In what kind of cases the Integer value will affect the value of the objective function? Second question: If the integer value affects the value of objective function, then what kind of errors will occur? I understand that there might be multiple situations/explanations for this warning. I just want to get the general concepts. Thank you. best regards, Li li