a puzzer about the circuit in RDR-189, 225 W 40 Inch LCD TV Power Supply Using PLC810PG

From RDR189 report:

4.5.3 Brownout Shutdown Circuit
A brownout shutdown circuit is provided. This circuit operates by sensing the AC input
voltage and the presence of a switching signal from the LLC controller. When the power
supply is operating, the absence of both of these signals, indicating insufficient AC input
voltage and insufficient B+ voltage at the input to the LLC converter stage will cause the
supply to shut down by switching off the primary bias regulator.
Components R24, R26, R28-30, C21, VR4, and Q7 are used to sense The AC input
voltage. The voltage threshold of this circuit is set below the turn-on threshold of the
standby/primary bias converter. Sufficient AC voltage triggers Q7, discharging capacitor
C22, which is charged via R15. Resistor R25 provides some hysteresis to prevent
chattering around the AC threshold voltage. Components R32, R35, and Q9 sense the
switching drive from the lower output FET of the LLC converter. Transistor Q9 discharges
capacitor C22 when the switching signal is present.
When the input voltage is sufficiently low, Q7 and Q9 turn off, allowing C22 to charge.
Components Q6, R21, and VR3 sense the voltage at C22. When C22 has charged
sufficiently, Q6 turns on, turning off the primary bias supply via Q4 and Q5, shutting down
the PFC and LLC stages.

Based on the caculating and deducing, the circuit in red circle is useless for the whole circuit. pls double ckeck.

Maybe I need to take some time to translate it into english.

The time constant of those components R28,R29,R30,R24,C21 is 0.2mS, while the main power period is 16.6~20mS, therefore , the transistor Q7 will experience OFF to ON to OFF in each main cycle. it takes about 168ms to charge C22 to 6.2V(5.6V+0.6V), In case of brownout, Vcc cannot be shutdown until 8~10 cycls of main power past . As far as R35,R32,Q9 is concerned, Due to its' high working frequency, Q9 will discharge C22 ONLY when Q7 is OFF. from the above analysis, the OFF time of Q7 in each main cycle is far less than 168ms, that's to say, suppose that Q9 will not work , C22 cannot be charged to 6.2V in a-off-time of Q7, if so, what's the function of R35,R32,Q9 ?
Let's review several thresholds in spec.
1. Standby power on threshold: set by R11: 4.7M*25uA=117.5Vdc , correspond to 83Vac.
2. PFC section: Vovp=385*1.05=404V, Vnominal=385V, Vo >100Vdc PFC on, Vo <88.5Vdc PFC off (11.5V hysteresis).
3. PFC output voltage >368V , LLC ON, PFC output voltage<246V , LLC OFF,

4. BROWNOUT section, power on threshold 104Vdc correspond to 73Vac (set by: R24, R26, R28-30,C21, VR4, and Q7) In case of brownout, power off threshold will be less than 104Vdc due to hysteresis from R25.

Based on these data: PFC output voltage will hold enough high(246V > 117.5Vdc ) after AC OFF as well as LLC OFF , this residual voltage can be sufficient to sustain TNY275 from shutdown. in the meantime, Neither BROWNOUT nor GATEL is available , so C22 can be charged to 6.2V to breakdown VR3 and shutdown PLC810
On the other hand, The requirement of HOLD_UP_TIME is 20mS, In case of AC main power off ., it will take 168mS for C22 to be charged to 6.2V to shutdown PLC810 , this duration is longer than 20mS hold up time, it's obvious that if the time for C22 to be charged to 6.2V is less than 20mS, the GATEL signal will be valuable to discharge C22 to insure hold up time can be met when AC main power off . If considering from cost , more delay time provided by R15,C22 would be the preferable solution than the one using GATEL signal to discharge C22 when AC main power off. Anyway, The GATEL signal is useless from the requirement of hold up time as per the parameter presented on the shematic.
In case of the test of fast turn on and turn off the main AC input, After AC main off and hold up time expired, the LLC section will shut down after the voltage of PFC buck capacitor is lower than 246V . then, there will be two situations

1. TNY275 is still running because the voltage of PFC buck capacitor is larger than 117.5Vdc, the voltage of C22 will be clamped to 6.2V due to neither BROWNOUT nor GATEL is available
2. TNY275 shut down because the voltage of PFC buck capacitor is less than 117.5Vdc, the capacitor C22 will be discharged slowly via R15.

Again after AC main power on to refuel , the threshold of brownout 104Vdc will be met at first , then C22 will be discharged completely by Q7, at the meantime,
the GATEL signal has not been born. that's to say,it's impossible of Q9 to discharge C22 after AC main power on .

Well , what on earth is the function of R35,R32,Q9 ?