It doesn't work that way. After a restart, SAF will be given a target without the condition of wicket lost at the end. So, if it indeed is for just 3'1 overs, target will be set regardless of how many wickets lost at the end - SAF will need to reach there.
Wicket calculation comes only if the game is stopped at a point after 20 overs and doesn't restart. Say, today after 25'6 overs DWL per is 130/2, or 144/3, or 162/4 - if it doesn't restart after that game will be settled there based on SAF's score. But, if it restarts for say 12 overs and SAF's target is set 234 in 38 overs, then there is no wicket condition here.
If they bring the game for 3'1 overs, I am sure target will be more than 28, but SAF will be massive favorite, with 8 wickets in hand, and it's a like T10 scenario, where we have seen 125 chased in 10 overs. .