Unrealized Profit

I was doing this question where premier had acquired sandford midyear and had to prepare the consolidated accounts. The problem is that sandford had made sales of 1 million each month of the year and related inventory left with premier was 2 million hence for URP it should be 2/12million × URP but when revenue was recorded only post acquisition intra group sales were subratracted , shouldn't the sales of whole year should be subtracted?