[Flugelbinder]

...Since you used spot metering, the 'spot' is by default at the dead centre of the frame...

On the K-5 II, the spot metering can be locked to the focus point, or be continuous - continues metering as you recompose. I use spot almost exclusively and find that it's more accurate (although I shoot manual) to have the exposure locked with the focus point, as it doesn't throw the needle as one recomposes.