It's AME. 6 months interval max, you say. You think I should stick with Mann oil filter as opposed to switching to Amsoil? Also, when reading the oil level on the stick, should it be in between the marks, or precisely at the top mark?

I don't know the exact reason, but I reckon my engine was consuming oil due to the following: Chevron dino oil 5w 30 doesn't perform well at long 5k interval; I tend to high rev a lot when I need that extra kick, not to mention my constant high speed driving; and the hot weather and city driving, as you've mentioned, can wear the oil down to start consumption in my case.

With Amsoil Synthetic, I was expecting no oil consumption at all; however, there's a bit of it around 4k and is evident at 5k. Mind you, it's not significant, and not as significant as Chevron, but it seems to be a normal occurance with our engine, perhaps?