The fallout takes only the people in the segment into account if they first did the steps before...
So in a 5 step process:
people who are in that last step had to do step 4 before, and step 3 before that, and step 2 before that, and step 1 before that....
In the table, each action is in isolation of one another.
The fact that your "total" UVs in your table is more than your step 1 UVs indicates to me that you have either a lot of people going straight to later steps (not doing step 1 - and possibly other early steps), or the user is doing this over multiple visits and losing their UV identification (maybe using incognito, maybe using a different browser, etc) but it means that that if a user isn't correctly identified as the same user, they could be lost in that fallout.....