Thanks for the feedback, updated my script. Fixed the HFSCORE, added a hours behind metric and now weighing top 21 accounts stronger for their price feed.

#!/usr/bin/env python3
import json
import datetime

HFSCORE = {
        "1.28.0": 100,
        "default": -30000,
        "nondef": -30000
        }
EXCHSCORET20 = {
        "0.059": 500,
        "0.060": 500,
        "0.061": 500,
        "default": -500,
        "nondef": -500
        }

EXCHSCORE = {
        "0.059": 50,
        "0.060": 50,
        "0.061": 50,
        "default": -50,
        "nondef": 0
        }

CFEETABLE = [
        [3.0, 5.0, 20],
        [5.0, 16.0, 50],
        [16.0, 49.0, 20]]

IRTABLE = [
        [0, 300, 100],
        [300, 700, 3000],
        [700, 1100, 1800],
        [1100, 1400, 500],
        [1400, 1800, 0],
        [1800, 2200, -1000]]

BAGE = [
        [0,4,0],
        [4,24,-600],
        [24, 24*5, -1800],
        [24*5, 24*14, -4000]]

MBTABLE = [
        [30000,100000,0],
        [100000,150000, 30]]

def getscore(val, table):
    if val is None:
        return table["nondef"]
    rval = table.get(val,None)
    if rval is None:
        rval = table["default"]
    return rval

def range_score(val, ranges, default, nondef):
    if val is None:
        return nondef
    for onerange in ranges:
        if val >= onerange[0] and val <= onerange[1]:
            return onerange[2]
    return default
    
def getval(key, obj):
    if "." in key:
        first, more = key.split(".",1)
        if first in obj:
            return getval(more, obj[first])
        return None
    if key in obj:
        return obj[key]
    return None

def numeric(val):
    if val is None:
        return val
    return float(val.split(" ")[0])

def hbd_update_age_score(witn):
    if "last_hbd_exchange_update" in witn:
        dt = (datetime.datetime.now() - datetime.datetime.fromisoformat(witn["last_hbd_exchange_update"])).total_seconds()
        if dt < 3600*2:
            return 40
        if dt < 3600*12:
            return 20
        if dt < 3600*24*2:
            return 10
        if dt < 3600*24*7:
            return 0
    return -300

with open("witnesses.json") as f:
    last_block_num = -1
    witnesses = json.load(f)
    for witness in witnesses["result"]:
        lcb = witness.get("last_confirmed_block_num", -1)
        if lcb > last_block_num:
            last_block_num = lcb
    wno = 0
    print("| score | witness | hours behind | apr | max-bs | creation-fee | exchange-rate | top 21 |")
    print("| --- | --- | --- | --- | --- | --- | --- | --- |")
    for witness in witnesses["result"]:
        wno += 1
        top21 = True
        if wno > 21:
            top21 = False
        behind = (last_block_num - witness.get("last_confirmed_block_num", -1)) // 1200
        score = 0
        score += getscore(getval("hardfork_version_vote", witness), HFSCORE)
        if top21:
            score += getscore(getval("hbd_exchange_rate.base", witness), EXCHSCORET20)
        else:
            score += getscore(getval("hbd_exchange_rate.base", witness), EXCHSCORE)
        score += range_score(numeric(getval("props.account_creation_fee", witness)),CFEETABLE, 0, 0)
        score += range_score(getval("props.hbd_interest_rate", witness),IRTABLE, -4000, -4000) 
        score += range_score(getval("props.maximum_block_size", witness),MBTABLE, -30, -30)
        score += hbd_update_age_score(witness)
        score += range_score(behind, BAGE, -30000, -30000)
        if score > 579:
            print("|", score, "| @" + witness["owner"], "|", behind, "|", 
                    getval("props.hbd_interest_rate", witness), "|", 
                    getval("props.maximum_block_size", witness), "|",
                    getval("props.account_creation_fee", witness),"|",
                    getval("hbd_exchange_rate.base", witness), "|", top21, "|")

New result:

score	witness	hours behind	apr	max-bs	creation-fee	exchange-rate	top 21
1440	@gtg	0	1000	65536	3.000 HIVE	0.059 HBD	True
1440	@stoodkev	0	1000	65536	3.000 HIVE	0.059 HBD	True
1440	@roelandp	0	1010	65536	3.000 HIVE	0.059 HBD	True
2640	@threespeak	0	600	65536	3.000 HIVE	0.059 HBD	True
1440	@guiltyparties	0	1000	65536	3.000 HIVE	0.060 HBD	True
2640	@abit	0	700	65536	3.000 HIVE	0.059 HBD	True
1890	@howo	0	1000	65536	3.000 HIVE	0.059 HBD	False
1890	@actifit	0	1000	65536	3.000 HIVE	0.059 HBD	False
590	@quochuy	0	1400	65536	3.000 HIVE	0.059 HBD	False
1890	@oflyhigh	0	1000	65536	3.000 HIVE	0.059 HBD	False
590	@techcoderx	0	1200	65536	3.000 HIVE	0.059 HBD	False
3090	@rishi556	0	600	65536	3.000 HIVE	0.059 HBD	False
1890	@neoxian	0	1000	65536	3.000 HIVE	0.059 HBD	False
3090	@brianoflondon	0	500	65536	3.000 HIVE	0.060 HBD	False
3090	@vsc.network	0	500	65536	3.000 HIVE	0.059 HBD	False
590	@hextech	0	1200	65536	3.000 HIVE	0.059 HBD	False
1890	@aliento	0	1000	65536	3.000 HIVE	0.059 HBD	False
1890	@sagarkothari88	0	1000	65536	3.000 HIVE	0.059 HBD	False
1890	@mengao	0	1000	65536	3.000 HIVE	0.059 HBD	False
1890	@c0ff33a	0	1000	65536	3.000 HIVE	0.059 HBD	False
3090	@holoz0r	0	570	65536	3.000 HIVE	0.072 HBD	False
1890	@liotes	1	1000	65536	3.000 HIVE	0.059 HBD	False
1890	@thebbhproject	0	1000	65536	3.000 HIVE	0.085 HBD	False
1890	@stresskiller	1	1000	65536	3.000 HIVE	0.059 HBD	False
1600	@innerhive	2	1000	131072	3.000 HIVE	0.137 HBD	False
3080	@condeas	0	500	65536	3.000 HIVE	0.061 HBD	False
1890	@hispapro	3	1100	65536	3.000 HIVE	0.059 HBD	False
1870	@whiterosecoffee	4	1000	65536	2.000 HIVE	0.059 HBD	False
1890	@borislavzlatanov	3	1000	65536	3.000 HIVE	0.059 HBD	False
2150	@sn0n	7	420	65536	1.000 HIVE	0.000 HIVE	False