4/4/4 in SFH 1×1, using 30 frequencies
RF LOAD = 3 / 30 = 10%
You are near the limit, so you should focus on down-tilting your antennas. The goal is to reduce at most the overlap between cells.
RF LOAD can be refined by replacing the # of TRX by the actual amount of (SDCCH + TCH) timeslots (in hopping TRXs) which are actually busy at the BH.
RF LOAD = (# busy TS @ BH / 8) / # of hop freq