FIX copy-paste error (sell versus buy)

Notes: please review carefully before accepting. patch propagation. manual test run. 
Reviewed By: https://github.com/dchichkov 
Cherry picked from:
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From 0d62bd70 Mon Sep 17 00:00:00 2001
From: Juanjo Menent <jmenent@2byte.es>
Date: Wed, 22 Jun 2016 18:59:51 +0200
Subject: [PATCH] Fix: Bad column totalizing if MAIN_SHOW_HT_ON_SUMMARY activated