Cant speak for Oceanic, not my part of the world.
In general if you are asked, its for a reason and quite often to help you - we have to 'sell' you to the next sector according to prescribed agreements, by taking higher it may well negate you having to take lower
However ill always try and explain this to pilots if the RT load allows.
At the end of the day if you get a request and you dont want to go higher, just reply with UAB, not brain surgery