disability and lump sum question

I received a lump sum last year which included 2020-2017. Now when I put in the lump sum which is box 5 on my SSA 1099 (which includes the payments I was supposed to get for those years) how do I know that when I put in the lump sums for the other years, the software isn't counting those as separate payments?  It seems like it is adding the included payments as separate payments.