Let's finish your example
OLD: (200+10) * 845.028800 (L76) = 177,456
NEW: (10+10) * 845.028800 (L76) = 16,900
Difference = 160,566 Less in new per day. Prior to the change the daily decay/member was roughly the same as a guild of 5 and now after the change it is reduced by over 90% for the guild of 200.