eso-pic code for page ornament changing geometry custom page settings to US-Letter

Question

I am trying to use this page decorating code given in this answer. But using this is ignoring my geometry page setting and changing page dimensions to US-Letter. How to debug this? How to correct this?

Edit1: I think memoir class is creating problem. When I ran same code with book class it works well. But I need memoir for other purposes. What is the solution to the problem?

This is MWE:

\documentclass[9pt]{memoir}
\usepackage[text={4.3in,6.95in},
%layoutsize={5.25in,8in},
papersize={5.25in,8in},
ignorefoot,
ignoremp,
headsep=11pt,
centering
]{geometry}
\usepackage{lipsum}

%%% Code from https://tex.stackexchange.com/a/159614/22840  --user11232
\usepackage{pgfornament}
\usepackage{eso-pic}
\newcommand\AtPageUpperRight[1]{\AtPageUpperLeft{%
 \put(\LenToUnit{\paperwidth},\LenToUnit{0\paperheight}){#1}%
 }}%
\newcommand\AtPageLowerRight[1]{\AtPageLowerLeft{%
 \put(\LenToUnit{\paperwidth},\LenToUnit{0\paperheight}){#1}%
 }}%

\AddToShipoutPictureBG{%
   \AtPageUpperLeft{\put(0,-25){\pgfornament[width=1.75cm]{61}}}
   \AtPageUpperRight{\put(-50,-25){\pgfornament[width=1.75cm,symmetry=v]{61}}}
   \AtPageLowerLeft{\put(0,25){\pgfornament[width=1.75cm,symmetry=h]{61}}}
   \AtPageLowerRight{\put(-50,25){\pgfornament[width=1.75cm,symmetry=c]{61}}}
   }

\begin{document}
\lipsum[1-40]
\end{document}