Update mode in RSA7(delta queue)

When i click one item in the delta queue to see the detail, i find there is two options to select. The default opion is ' delta update' and the other is 'delta repetition'.

I think there are two versions data saved in delta queue. One is to be delta updated that displayed as we select 'delta update' option. The other is the last delta updated to be saved to make REPEAT DELTA available.

Could any expert give me advice for my opinion.Thanks a lot.