Second paragraph: "The perigee, or low point of its orbit, has dropped by a similar amount, which is consistent with pre-flight expectations for the effects of

Second paragraph: "The perigee, or low point of its orbit, has dropped by a similar amount, which is consistent with pre-flight expectations for the effects of atmospheric drag on the spacecraft." Basically, they're using the sail to boost their apogee while at the same time drag is bringing the orbit as a whole down.