[Q] SIP Qualify latency

[lleo_]

I am testing the W52P with a local Asterisk 1.8.23 server. All extensions and trunks have the SIP setting qualify set to yes to monitor their availability.
For some reason, the W52P consistently shows a latency of of ~130 ms, increasing to ~160 ms when on a call.
Everything is on the same subnet and same switch and no NAT. Other endpoints have a single-digit latency, including another DECT offering from a competitor.
This 130 ms latency is actually worse than my slowest trunk.
While I am not finding any issue that can be linked with this latency, I have had occasional dropped call and some voice quality issues, nothing that I could reproduce. It leaves me to wonder if this could be causing some problems somewhere...
Any opinion on this?