OK, I've done the maths again.
Assuming Louis top in the votes, Lisa second and Denise bottom then we have two possibilities. If Dani is third with the public and Kimberley fourth then Denise and Lisa are in the dance off with 5 points each, Lisa goes home. If Kimberley gets more votes than Dani (unlikely IMO, but you never know, because those were very crowd pleasing dances) then Denise and Dani would be in the dance off and Dani goes home.
If Lisa is getting more votes than Louis then Denise and Dani will be in the dance off, no matter which way the other votes go.