Bad tie placement

[Abraham Lee]

My LP Friends,

While scoring a song, I noticed a rather poor tie placement in a chord. 
Here's the code:

\version "2.18.2"

music = \relative c'{
 \key aes \major
 \time 2/2
 \numericTimeSignature
 \partial 2 g'4 ( f ) |
 <c ees>4 ees <c ees> <bes ees> |
 bes'2. ees,4 |
 <des ees-\tweak color #red ~ aes~>1_( |
 <c ees aes>2. ) \bar "|."
}

\paper {
 paper-width = 7\in
 ragged-last = ##f
 indent = 0
}
\header {
 tagline = ##f
}

\markup "\voiceOne, ragged-last=##f, bad tie placement"
\score {
 { \voiceOne \music }
}

\markup "\voiceOne, ragged-last=##t, normal voiced tie placement"
\score {
 \layout {
   ragged-last = ##t
 }
 { \voiceOne \music }
}

\markup "(default voice), ragged-last=##f, normal non-voiced tie 
placement"
\score {
 { \music }
}

See the attached file for a picture of the above issue (bad tie 
indicated in red). 

1. In the first system, and in my song, all the notes need to be 
\voiceOne. The default placement of the ties is "up", but the placement 
is horrid on the ees in the last two measures. If I manually flip it 
down, then it looks great (which I've gone with). This appears to be an 
issue with the length of the system because ... (see #2).

2. When I shorten the system (i.e., ragged-last = ##f), then the 
default, voiced tie placement is as I would expect it.

3. When I make the system be the same length as the original, and 
either manually switch the direction or remove the explicit \voiceOne, 
then the downward tie also places perfectly.

4. (Not shown) If you extend the paper-width to be something like 
10\in, then the default, voiced tie is once again placed correctly (but 
not at 9.99\in).

I guess all I'm saying is that from paper-width of 5.8\in to 9.99\in, 
and forcing everything into \voiceOne, the ties are placed incorrectly 
than outside that range. Any ideas what's causing it?

Regards,
Abraham

bad-tie-placement.png
Description: PNG image