Of course it is your bitcoin but it is now impractical to work out the right fee manually.
Sticking on 0.5.11 means you may create tx that don't propagate or take ages to confirm. It is your choice of course but my aim is to get people's transactions out in the network, propagated and confirmed as painlessly as possible for everyone.
Well, you're right. I'm sorry for my ignorance and thank you for detailed explanation.