Got an oil change recently. I knew it had 1qt of 10w30 mobil super. Anyway i have a bad valve cover gasket and the oil will slowly leak out of it. After my oil change i looked at the receipt and found that they used service pro 5w30 synthetic blend oil. Well its been about 3 weeks and it hasn't leaked a drop. I found this surprising because its thinner oil so i thought it would've leaked faster but it hasn't leaked at all. Is that good or bad? Not sure....