음... 같은 내용이, 여기저기에 흩어져 있어서 뭘 기준으로 해야하는지...
아무튼, 다음은 이전의 답을 조금 수정한 것입니다.

\documentclass{article}

%\usepackage{mathtools, graphicx}
%\usepackage{amssymb}
%\usepackage{extarrows}
\usepackage{tikz}
%\usetikzlibrary{decorations.text}
%\usetikzlibrary{backgrounds,shapes} %pictures
\usetikzlibrary{arrows}%,automata}

\begin{document}

\tikzset{main node/.style={circle,draw,font=\sffamily\Large\bfseries}}
\tikzset{text node/.style={inner sep=2pt,font=\sffamily\Large\bfseries}}

\begin{tikzpicture}[->,>=stealth',node distance=3cm,thick,shorten >=5pt,shorten <=5pt]
\node[text node] (1) {TEST A $+$ TEST B};
\node[main node] (2) [right of=1,node distance=5cm] {C};
\node[main node] (3) [right of=2] {D};
\node[main node] (4) [right of=3] {E};

\def\myshift{2pt}

\path[every node/.style={font=\sffamily\small}]
  ([yshift=\myshift]1.0) edge node [above] {$h_{1}$} ([yshift=\myshift]2.180)
  ([yshift=\myshift]2.0) edge node [above] {$h_{2}$} ([yshift=\myshift]3.180)
  ([yshift=\myshift]3.0) edge node [above] {$h_{3}$} ([yshift=\myshift]4.180)

  ([yshift=-\myshift]2.180) edge node [below] {$h_{-1}$} ([yshift=-\myshift]1.0)
  ([yshift=-\myshift]3.180) edge node [below] {$h_{-2}$} ([yshift=-\myshift]2.0)
  ([yshift=-\myshift]4.180) edge node [below] {$h_{-3}$} ([yshift=-\myshift]3.0)  

  (2) edge [bend right=45,pos=.125] node [above] {$h_{-1}^{*}$} (1.60)
  (3) edge [bend right=45,pos=.3] node [above] {$h_{-2}^{*}$} (1.100)
  (4) edge [bend right=45,near start] node [above] {$h_{-3}^{*}$} (1.135);

\end{tikzpicture}

\end{document}