The formula seems to be
immortal score = XP * multiplier
where multiplier is determined by your immortal rank (number of remorts).
After looking at some entries on the ranking board, dividing immortal score by XP, I found:
Rank  Multiplier
45  2.45
23  2.23
20  2.20
21  2.21
12  2.12
9  2.05
7  1.95
3  1.60
2  1.40
1  1.20
So, for the first few remorts your multiplier increases rapidly, but when you reach the higher ranks the benefit of additional remorts is not so great.
Rank 14: multiplier increases by 0.20 for each remort.
Rank 510: multiplier increases by 0.05 for each remort.
Rank 11∞: multiplier increases by 0.01 for each remort.
__________________
Last edited by Lourens; 11222012 at 11:17 AM.
