P indicates the connection is "partial", which means it exists in the Firewall Worker connections state table but not in the SecureXL connections table. This can happen if a connection already existed when a state change occurred in SecureXL (disabled then enabled, or if other SecureXL features like NAT Templates or Drop Templates had their configuration changed). This is normal and just keeps SecureXL from accidentally dropping those packets, to ensure they reach a Firewall Worker for correct handling; obviously that traffic will not be fully accelerated by SecureXL.
Fully accelerated traffic will normally have no flags set, but A (Accounting), N (NAT), and C (encrypted) may appear depending on the connection attributes and it will still be fully accelerated. Generally speaking the presence of any flags other than these three indicates the connection is not fully accelerated and being handled on a Firewall Worker in the PXL/F2F/QXL paths. So your "...AC..S......" connections are Medium Path (PXL). I don't know what the numbers mean at the end of the line.
You said "I have excluded the TCP Port 55559 from any IPS inspection". If you used an IPS/TP exception to do this it will have no effect on acceleration status; an exception simply changes the decision rendered after inspection. You need to use what I call a "null profile" to make that traffic eligible to be fully accelerated, in your TP policy create a rule matching the 55559 traffic and match it to a TP profile action that has IPS completely unchecked. Even if you do so, there may still be some other blade keeping the traffic from being fully accelerated depending on your configuration.
Dependent on the minor version of your gateway and Jumbo HFA level you may also be able to force the 55559 traffic to be fully accelerated with the "fast_accel" directive, but this option should be exercised with caution.
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