Can't override Ext.form.Labelable.getLabelCellAttrs

[delegans]

Before, field label style is valign="top"

<td id="filefield-1082-labelCell" style="" valign="top" halign="right" width="245" class="x-field-label-cell">
<label id="filefield-1082-labelEl" for="filefield-1082-inputEl" class="x-form-item-label x-form-item-label-right" style="width:240px;margin-right:5px;vertical-align: middle;">
Label:
</label>
</td>

Try to override Ext.form.Labelable and set valign="middle"

Ext.override('Ext.form.Labelable',{
    
    getLabelCellAttrs: function() {
        console.log("I'm here");
        var me = this,
            labelAlign = me.labelAlign,
            result = '';


        if (labelAlign !== 'top') {
            result = 'valign="middle" halign="' + labelAlign + '" width="' + (me.labelWidth + me.labelPad) + '"';
        }
        return result + ' class="' + Ext.baseCSSPrefix + 'field-label-cell"';
    }
});

After, field label style is valign="top" anyway:

<td id="filefield-1082-labelCell" style="" valign="top" halign="right" width="245" class="x-field-label-cell">
<label id="filefield-1082-labelEl" for="filefield-1082-inputEl" class="x-form-item-label x-form-item-label-right" style="width:240px;margin-right:5px;vertical-align: middle;">
Label:
</label>
</td>

Does override bug or I something misunderstand?