I agree, but actually I still don't believe in "Balkenkreuze", because on the upperside, the
Me 163, as most other German aircraft carried a dark "splinter camouflage" with only four
relatively thin white brackets, as a kind of "low viz" markings. There seems to be too much
white there, but those grainy photos can play tricks on us.
Think I've seen the same sequence in Mano Zieglers book "Raketenjäger", maybe quality is
better there, will have a look this evening.
EDIT: Google is your friend and the answer may be here http://robdebie.home.xs4all.nl/me163/kelb.htm:
"...
One last note: I received several e-mails about the 'roundels' visible on the wing. This suggests the sequence shows a captured aircraft, crashing during an evaluation flight. Indeed the wing markings look like white circles, but they are composed of the corners of the iron cross. The photos in the Ransom/Cammann book show this slightly better. Also, no powered test flight were performed after the war, making it impossible that this is a captured aircraft. ..."
Although there are discrepencies, too, as other sources state, that Eric Brown actually made a powered flight (unofficially !) ...