The vbulletin system limits giving out rep to the same member, to at most, once every 24 hours.
The rationale behind this is to insure that members can't neg rep, or plus rep someone a lot, in order to quickly raise, or destroy their rep.
Currently the system is set to allow a maximum of 5 reps to be given out in a 24 hour period. After a rep is given you also must give rep to at least 50 other, different members, before you can give it to the same member again.
So it comes down to two numbers... how many reps can be given out in a day, and how many OTHER members you must rep before leaving rep to the same member again.
10:20 ratio we had before, meant you had to give out at least 20 reps to other members before you could give a rep to the same member before. 10 was the maximum amount of rep you could give out in a day period. Which meant in essence a minimum of a two day cool off period before another neg rep from a member, though in practical terms, very very few members ever reached even those limits. Alaskan ran through his as a matter of protest, deus ex machina style handing out +reps to any and all, meanwhile Cyparagon repped inactive members but to be able to leave neg reps. For the most part it all went unnoticed, until the recent trolls USAbro, Starkiller, and VisibleGreen, all three of whom did not respond well to seeing neg reps from multiple members.
That brings us to today... and hoping the trees start to bloom:shhh: