Ok, the reason SKU showing on some pages and not on others is because I initially didn't count on paroduct variant's SKUs.
To remove all SKUs from customer side (including product variants one), right after you initially modified your
/customer/main/product_details.tpl , find :
Code:
<td class="property-name">{$lng.lbl_sku}</td>
<td class="property-value" id="product_code">{$product.productcode|escape}</td>
and replace it with :
Code:
<td class="property-name">{* {$lng.lbl_sku} *}</td>
<td class="property-value" {* id="product_code" *}>{* {$product.productcode|escape} *}</td>
Enjoy