May be they indicates Uplink RxQual value and Downlink RxQual values.
And you might know that RxQual values are related to BER.Lower value of RxQual means good quality and higher value means poor quality.
RxQual should be poor where there is interferences.Good level and poor RxQual indicates that there is interferences.
Besides,Poor level also cause poor RxQual.
(So u can ovserved combined measurment graph for RxQual and RxLevel, and if u find poor qual due to poor level then its ok,but if u find level is good and qual is poor then might be interferences.)