Yes in SFH its mandated to establish MAL twice or more than your TRX in sector.
BUT see that: the main idea of the hopping is to averaging the interference in all channel. SO as more as you add freq to MAL above the twice no of TRX per sector as you have better performance based on quality enhancement.
Cuz you deal here with (frequency selective fading). & any environment has a certain coherence fading (the BW between two frq which it high correlated for fading).
Rural: delay spread(low)===>coherence fading is high===>need large BW of MAL to deal with such fading seemed to be flat fading.
Urban: delay spread(medium)===>coherence is medium==>need medium MAL BW.
Dence urban: delay spread(high)-=>coherence is small==> need low BW MAL.
AND INDOOR: delay spread is tooo small==>coherence fading is tooo large (flat fading) ====> need tooooo large BW MAL to deal with such fading (not practical),