I am designing multiple (about 5 to 6) BATES grain for an upcoming motor, during the simluation in open motor is it compulsory to the inhibited ends as both for the middle grains and top for the first grain

the reason being I want to get a nuetral curve with the BATES geometry but when i change the inhibition type the curve becomes progressive

so I want to understand how the software considers this parameter and simulates the grain