Separating bow marks from notes

[lesmondo]

Hi,

I'm trying to separate bow marks/fingerings from notes and the bow marks/fingerings don't align with the notes correctly. 

What am I doing wrong?

An example shows my problem.  

\version "2.14.2"

notes = { c d e-4\upbow f-4\upbow }

marks = { s-4\upbow s s s-4\upbow}

\score { \new Staff <<\marks \notes >>}

Thanks

Les