Your climate in Malta is a lot warmer than it is here in the UK so the oil you use
( what oil do you use? ) should never have an issue with it taking a long time to run back down into your sump.If your engine/turbo is in tip top condition and you fill it with the correct amount of oil it should not be using oil and the level should stay the same. I have never heard of this problem that you have and there does not seem to be a logical reason for it to happen. Check the oil level before you take the car out and there is no reason why when you check it again it will be different. An engine can only use oil through valve guide seals, worn piston rings, turbo oil seals or actual oil leaks. If your engine has none of these issues the oil level should not change.