I will tell you what involves your idea.
1. Level of duel = Level of your character + Sum of all points gained by duel
This sum has a correspondent in a table. A part of the table is shown below:
Sum of duel points ----- Level Value
47 ========> + 1 Level
148 ========> + 2 Level
290 ========> + 3 Level
468 ========> + 4 Level
679 ========> + 5 Level
920 ========> + 6 Level
1189 ========> + 7 Level
1486 ========> + 8 Level
....................................
If your character level is 50 and also you have 30 point gained by duel =>
Your level o duel = 50 + 1 = 51
2. Second, points gained by duel are calculated using the formula:
Points = (7 * level of defeated player) - (5 * level of winner player) + 5
Based on this formula we can determine the range of players who can attack.
Example: Always points obtained by duel must be greater than zero. =>
(7 * level of defeated player) - (5 * level of winner player) + 5 > 0 =>
To solve this equation => (7 * level of defeated player) - (5 * level of winner player) + 5
= 0
After that, we can we can determine the range of players who can attack. [the range of players who can attack based on above formula was posted by first time by warrigal in old post in January 2009]
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In summary:
a. If we decrease the character level because also want we to decrease level of duel => we can do the game missions corresponding to our level.
Example: my character level is 67, after decrease become 60 level. We can do quests and missions for level 67 just only missions for 60 level.
b. If we decrease Sum of all points gained by duel because also want we to decrease level of duel => the top list of duellist become inconsistent.
Frequently I talk with Geronimo about duel:
http://www.youtube.com/watch?v=Eum4xW4c4X8&feature=related