Code:
<div class="save" id="save_percent_box"{if $product.appearance.market_price_discount} style="display: none;"{/if}>
It means "If there is a discount - hide the discount label"
You should change it to
Code:
<div class="save" id="save_percent_box"{if $product.appearance.market_price_discount eq ''} style="display: none;"{/if}>