It's better to just replace the oil wholesale.

What the additive is doing is probably sealing leaks where the oil was entering the combustion chamber... what color was the smoke coming out of the tailpipe?

Heck... ganyan ang style ng mga ibang buy-and-sell... stuff the engine full of heavy oil... wala na yung usok... but the additive adds friction, which means you'll have to change oil sooner or risk breaking something.

I'd just go for a 15w40 or 20w50 turbodiesel compatible synthetic for the Pajero.