7z seq compression working

UnzipSeqArchv.bat

@@ -1,5 +1,5 @@
 @echo off
-setlocal EnableExtensions
+setlocal EnableExtensions EnableDelayedExpansion
 
 set "REN_DIR=%~dp0"
 for %%I in ("%REN_DIR%..") do set "PROJ_ROOT=%%~fI"
@@ -31,12 +31,12 @@ if not defined PY_SCRIPT (
 pushd "%PROJ_ROOT%" >nul 2>&1
 
 python "%PY_SCRIPT%" --mode expand --verbose %*
-set "ERR=%ERRORLEVEL%"
+set "ERR=!ERRORLEVEL!"
 
-if not "%ERR%"=="0" (
-    echo Failed to expand render sequence archives (exit code %ERR%).
+if not "!ERR!"=="0" (
+    echo Failed to expand render sequence archives (exit code !ERR!).
 )
 
 popd >nul 2>&1
-exit /b %ERR%
+exit /b !ERR!