Does my car need overhaul?

[Kitt]

Hi Folks,

Its been a while since my last post here hehe

So my car is a 2005 Yaris Hatchback, 2NZ engine with 235000km (143000 miles), never overheated, maintenance up to date, no strength loss (not that im aware of), no check engine lights and no oil leak or smoke. It works just fine. I measure the drained oil when I change it and it returns 3 out of 4 quarts and that is what concerns me. I used to do an engine flush after an oil change (did this about 3 or 4 times) and I think that is what caused it, however, I am using an oil additive and the oil loss has decreased. I've been told that due to the engine age it needs overhaul but I've also heard that the oil "loss" is not that critical. so, do I need to overhaul it or not?