如何更改发票的默认顶部边距？

Question

以下是我得到的信息：

\documentclass{letter}

\newcommand*{\BottomLeftX}{1.0in+\hoffset+\oddsidemargin}%
\newcommand*{\BottomLeftY}{\paperheight-1.0in-\voffset-\topmargin-\headheight-\headsep-\textheight}%

\newcommand*{\AbsolutePosition}[4][]{%
    % #1 = tikz options
    % #2 = x (from south west corner of page
    % #3 = y
    % #4 = text
    \begin{tikzpicture}[overlay, ultra thick]
        %\draw [shift={(#2,#3)},#1]  (current page.south west) circle (2pt) 
        \draw [#1]  ($(current page.south west) + (\BottomLeftX,\BottomLeftY) + (#2,#3)$) 
            %circle (2pt) %  adding `[opacity=0.2]` to the node below will let you see this reference point
                node[] {#4};
    \end{tikzpicture}%
}

\usepackage{float}
\usepackage[english]{babel}
\usepackage{fix-cm} 
\usepackage{marvosym}
\usepackage{auto-pst-pdf,pst-barcode}
\usepackage{background}
\usepackage{amsmath}
\usepackage{ textcomp }
\usepackage{graphicx}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{textpos}
\usepackage{pstricks}
\backgroundsetup{%
  scale=2,       %% change accordingly
  angle=0,       %% change accordingly
  opacity=.2,    %% change accordingly
  color =black,  %% change accordingly
  contents={\begin{tikzpicture}[remember picture,overlay]
        \node at ([yshift=-5pt,xshift=0pt]current page.center) {\includegraphics[width=5cm]{filmax.jpg}};
    \end{tikzpicture}}
}
\usepackage[usestackEOL]{stackengine}
\edef\tmpbs{\the\baselineskip}
\setstackgap{L}{\tmpbs}
\newlength\tmpwd
\newlength\tmpht
\usepackage{invoice}
\fboxrule=1pt

\let\svaddress\address
\renewcommand\address[2][]{%
  \ifx\relax#1\relax\svaddress{#2}\else
  \def\theaddress{#2}\invoicenote{#1}\fi}

\def\invoicenote#1{%
  \def\stackalignment{l}
  \setbox0=\hbox{\expandafter\Longstack\expandafter{\theaddress}}
  \tmpwd=\wd0\relax
  \tmpht=1.5cm %\ht0\relax
  \def\y{\fboxsep=0pt\fbox{\rule{0pt}{\tmpht}%
    \stackon[\tmpht-\tmpbs]{\rule{\dimexpr\textwidth-\tmpwd-3cm\relax}{0pt}}%
    {\hspace{0.23cm}~\textsf{\strut {\color{red}INVOICE}}~~\smash{\Longunderstack{#1}}}}}
  \svaddress{\llap{\y\hspace{0.31cm}}\expandafter\Longstack\expandafter{\theaddress}}
}

%  ANY OF THESE FORMS WILL WORK:
%\address{\emph{Invoice from:} \\ My Address \\ My Address \\ My Address}
%\address[~]{\emph{Invoice from:} \\ My Address \\ My Address \\ My Address}
\address[\footnotesize Attention to: \hspace{0.15cm}Master of Provisions\\ \footnotesize Your Ref.\textnumero:\\ \footnotesize Our Ref.\textnumero:\\ \footnotesize Credit Terms: NET 15]{\emph{Invoice from:} \\ {\tiny My Address} \\ My Address \\ My Address}

\signature{Tin Tin}
\date{Hong Kong, Thu Apr 24 2014}
\begin{document}
  \begin{letter}{\emph{Invoice to:} \\ {\tiny To Address} \\ To Address \\ To Address}
    \opening{Invoice no. 0000000001}
    Hello, and good evening\footnote{My representative's name is Georges Prosper Remi.}.
    \begin{invoice}{USD}{0}
      \ProjectTitle{Invoice}%
      \Fee{Database Maintenance} {12999.99} {1}
      \AbsolutePosition[fill=red,draw=red]{4.1cm}{-7.21cm}{\includegraphics[scale=0.5]{sig.png}}
    \end{invoice}
    \closing{\emph{Invoice Release Authorization:}}
\vspace{0cm}
%\begin{pspicture}(0.5in,0.5in)\psbarcode{0000000001}{eclevel=L}{qrcode}\end{pspicture}\hspace{5cm}
 %\includegraphics[scale=0.3]{foot.png}
\fbox{
    \parbox{11.54cm}{
        ~\textsf{{\color{red}COMMENTS}}
        \vspace{1.5cm}

        \hspace{9.25cm}{\tiny Master of Provisions}
    }
}
\begin{textblock}{10}(-0.5,1.25)
\centering
Thank you for your business. \\ \vspace{0.5cm}\fontsize{10}{10}\selectfont {\Large\Letter} [email protected] \hspace{0.2cm} {\Large\Telefon} +1 (555) 555 - 5555
\end{textblock}
  \end{letter}
\end{document}

我正在尝试弄清楚如何更改默认的上边距，以便页面上可以容纳更多内容。上边距太大了...这是为什么？