it is a trade off between CPU processig capacity for a)paging and b)Location updates. So, one of the CPUs may report overload if we hit the limits. I did never see an algorithm/tool for full calculations and it would also change with every new hardware release or software. Be happy, if 1 LA/BSC works fine. Recently introduced features such as “Precise Paging” may reduce the paging load within the LAC, if the algorithm can remember the last cell of the mobile.