dear aspirant,

 In cet mock allotment,  You are alotted a college based on your option entry but that is not necessarily the college you will join/get later. You just get an idea of the entire allotment procedure. In case you've made a mistake in your choice entry, you can correct it after the mock allotment.You can also check the cutoffs of the mock allotment and re-arrange your options if required. And about the dates it may vary according to the status.

hope it helped.