OWASP CRS Anomaly scoring, ModSecurity WAF

OWASP CRS Anomaly scoring, ModSecurity WAF

I'm getting into OWASP CRS with ModSecurity and was investigating the way OWASP calculate the anomaly score in the REQUEST-901-INITIALIZATION.conf they set the following lines:

setvar:'tx.anomaly_score=0',\
setvar:'tx.anomaly_score_pl1=0',\
setvar:'tx.anomaly_score_pl2=0',\
setvar:'tx.anomaly_score_pl3=0',\
setvar:'tx.anomaly_score_pl4=0',\

and in the REQUEST-949-BLOCKING-EVALUATION.conf they do the following:

SecRule TX:PARANOIA_LEVEL "@ge 1" \
    "id:949060,\
    phase:2,\
    pass,\
    t:none,\
    nolog,\
    setvar:'tx.anomaly_score=+%{tx.anomaly_score_pl1}'"
enter preformatted text here
SecRule TX:PARANOIA_LEVEL "@ge 2" \
"id:949061,\
phase:2,\
pass,\
t:none,\
nolog,\
setvar:'tx.anomaly_score=+%{tx.anomaly_score_pl2}'"

Q1: Of course the paranoia level will be 1, 2, 3 or 4, so why do the "@ge 1"? which will be evaluated on every paranoia level?

Q2: When they do the setVar "setvar:'tx.anomaly_score=+%{tx.anomaly_score_pl2}" the equation will be tx.anomaly_score=tx.anomaly_score+tx.anomaly_score_pl2; is that right ? And how is this logically applicable if my request is being validated by multiple rules?

Q3: I would like to have a detailed example of how the OWASP CRS calculate the anomaly score and use it to deny the requests.