The tie continued on a next line is not influenced by positioning override. Instead, it's placed per default positioning. How can one move these continued ties or slur?
\version "2.18.2"
pushTieDown = \shape #'((0 . -1.0) (0 . -1.2) (0 . -1.2) (0 . -1.0)) Tie
{
\stemDown
\repeat unfold 16 { s4 }
s2 \pushTieDown a'_~ \break
a' s
\repeat unfold 16 { s4 }
}