When should you change up your weekly goals?

So I've seen a few people in the forums say things like 'with that little left to lose, you should be aiming for 0.5lb a week' and similar, and it got me wondering - when is the right time to change up what you're aiming for?

I started off at 13 stone(182lb) with a GW of 10 stone (140lb) and am currently at just under 11 stone (152lb to be precise :D). I am 5'6".

My MFP was originally set to lose 2lb a week, (and was therefore at 1200cal.) but I realised very quickly that was a sad amount and upped it to 1300. When I hit the 2 stone (28lb) mark I upped it to 1400 cal. So now I am 12 lb from my goal, should I be upping my intake more? Apart from the first couple of weeks, I've actually pretty consistently lost 2lb a week. Maybe I should just not fix what doesn't appear to be broken?