brackets should be independent from each other, the only thing they are "building up" is total number of players, who gets 15or more HK per week.
The % is based on total PvP playerbase:

We got ~15-16k total players in standings so:
Bracket 1 (12-13k RP) should be ~1-30 standings and ~1-45 standings during 1.12 buff
Bracket 2 (11-12k RP) should be ~31-105 ST and 46-120 ST 1.12
Bracket 3 (10-11k RP) should be ~106-255 ST and 121-300 ST 1.12
Bracket 4 (9-10k RP) should be ~256-555 ST and 301-525 ST 1.12
Bracket 5 (8-9k RP) should be ~556-1155 ST and 526-900 ST 1.12
Currently this system isnt working correctly, because you can even with ~400 standing get only ~8k RP.
Are % "nerfed" deliberately or there is some bug? Still thats not blizzlike...
And most ppl prefer blizzlike experience, including honor system.
Also looks like #1 person from 1-st Bracket honor/week affect players from ALL brackets while calculationing RP gain... Thats not blizzlike too.
Best Regards!