PF & altq benzedrine.cz prioritizing ACK packets

[andrei.manescu at clicknet.ro]

Hello everyone. 

I've stumbled upon this article at http://www.benzedrine.cx/ackpri.html 
about prioritizing ACKs and the pass out/pass in rules are for packets with 
flags S/SA (SYN flags = set, ACK flag = unset, rest = ignored). 


In the pf manual I found: 

pass in on fxp0 proto tcp from any to any port ssh flags S/SA 

The above rule passes TCP traffic with the SYN flag set while only looking 
at the SYN and ACK flags. A packet with the SYN and ECE flags would match 
the above rule while a packet with SYN and ACK or just ACK would not. 

So now I wonder how does Daniel Hartmeier's rule prioritize ACKs packets 
when these packets don't even match that rule ??
That rule is only for packets that have SYN flag set, ACK flag unset and the 
rest of the flags set/unset. 

I would apreciate an explanation. 

Thank you in advance.
Andrei.