@PavelV 

Hey

I notice you have 2x WAN links setups  (WAN and WAN/LAN1) is this correct that you have 2 internet connections?

If so then the filter wont kick in until its 90% of the combined speeds, namely 36 down 9 up.   If you have only 1 connection to the WAN then disable the second WAN1 connection and this should work ok for you.   Having 2x connections listed to the same router will fudge the connection speed.  

P.S.  I personally would drop this down to 75 or 80% before kicking in, 90% is too close to the max.     Lets be honest, you wont get perfectly 10 up 20 down most of the time, it may be 19 down and 8.7 up..   90% is just too close for wiggle room that it may infact not trigger the filter because your connections isnt running totally the 20/10 ypu have paid for .   75/80% gives you enough wiggle room to avoid any issues with line speeds