Increasing MFRMS(no. of Multiframes between paging), will summon no. of paging groups increasing that’ll create delay in call set-up time as Mobile has to wait for paging group for long time.[formul for No. of paging group N:=(9-noofblocksforAccessGrant)*MFRMS[for non-BCCH combined].
Paging group N:(IMSI mod 1000)mod N.//that means N is proportional
if MFRMS decreases no. of paging group will decrease & then no. of IMSI in one paging group will increase.Increasing MFRMS will also reduce cell reselection sensitivity but saves lot of battery power of MS.