Issue found when doubling position - 1 position, 2 Entry Prices

Hi Guys, 

I've found a potential issue, or maybe it's just a question to be clarified:

I have 1 (single) Buy position open, which i have Doubled Up. I notice that when Doubling, the position is averaged, as expected. 

However, i noticed that if you double a position, it maintains 2 separate entry prices within the single position, when partially closed.. 

Please notice the attached images, highlighting the different entry prices, but same position.  Could you clarify what's occurring here?