MS is measuring the BCCH level of each neighbour and reporting the 6 strongest to the BSC.
The neighbours are not “sending” the RxLev.
Rxlev is a measurement !
different between MS Power control and BS power control
MS PC : it is the Tx Level of the MS, absolute power.
BS PC : it is the Tx level of the TRX (on that timeslot). The value shown is an “attenuation” compared to the max power of the TRX (= relative power).