you or the body shop would have to be nuts to allow a blend for a front bumper repaint.
I saw your other post and thats not a blending problem but a hack body shop that i would't go back too. Also I'd verify the kms if you drop it off again because the only plausible explanation for that paint job is that they wanted to re-test drive your car.
Thats a horrible paint job. I know my local body shop has a paint scanner that matches paint 85-95%. Get to a better shop.
UNDER NO CIRCUMSTANCES would i allow them to blend !
2016-F82 M4 MW DCT
2013-F10 M5 B&O AMS DP DCT (GONE)
2014-F32 435xi AW 6SP (SOLD)
2006-E90 325i winter ride