This setting only affects Accounting Reports.

@Ray : that's right, my bad
@mathieu : do you have Studio ? If yes, you could have to modify your reports
Something like this :
<t t-elif="line.display_type == 'line_section'">
<td name="td_section_line" colspan="99">
<span t-field="line.name"/>
</td>
<t t-set="current_section" t-value="line"/>
=> this line <t t-set="current_subtotal" t-value="0"/>
</t>