et/mph reflectors

i noticed at atlanta this weekend after the prostock bikes ran that a top end track worker would remove black et + mph reflector shields in the middle of the track that covered the "normal" reflectors. it appeared that the bike reflectors were lower than the ones used for all other runs. is ths something nhra started doing to "fix" their win light bike problems from indy? have they mentioned anything about this being a solution to that problem? could the lack of removing these lower reflectors be the reason they had goofy ets at several races in the past? it appeared from the top end bleachers that the bike reflectors were at least 2" lower to the ground that the "normal" reflectors.