I have some 50pcs sample 1206 10uF ceramic caps that I got from AliExpress the other day. Purported to be X7R. I measured them (7 of them at least, it's tiresome to pick them up with pincers from the reel and put them back) with my DMM and they all checked in at between 9.5 and 10.1 uF or so. After having soldered two of them for prototyping, and heated them somewhat obviously, they measured at about 10.5 uF so not much of a change either. Is this information enough to say that the rating for these caps is good enough? Can't prove that is is X7R or whatever I mean, but that they at least can't be bottom of the barrel so to speak ...