System battery info conflicting?

[AndyK]

So my new rMBP is just under two weeks old & I have calibrated the battery today.

Something I'm finding weird is that the battery remaining percentage is showing as one value in the system display & then any other third party apps are showing a different value.

For example, at the moment the OS is showing %age as 96%.

However two separate apps that show battery status are showing it around 91%.

Battery Health

iStat Pro

As I said I've calibrated & also reset the SMC. Any reason this could be happening or is it normal?

 

[AndyK]

As time goes on it seems the difference is consistently 5%.

 

[AndyK]

No one have any ideas? Not getting very far on google : (