i think you might have misread the numbers some. they tested with the igp, the r7-250 alone and then with dual graphics.
i did notice the 250 being behind the igp but in just about every case the dual solution was better by a long shot. only gta v lost ground with the dual solution. overall i'd say the $40 is well worth it considering the fps was almost double with the dual solution.
if i had the a10 i'd go for it for only $40 more.