ok to shorten server expires setting to 3 minutes?

I have a home LAN with 5 ip phones (all yealink), and they all use 3cx running on a laptop on the LAN. I noticed recently that when my 3cx server reboots it takes a really long time (10-20 minutes) for 4 of the 5 phones to be listed as registered on 3cx's console even though the phones themselves identify themselves as registered when I go to their webpage interfaces.

The one that registers quickly has a server expires setting of only 180 seconds while the other four phones have server expires settings of 3600 seconds (the default). When I change those settings to 180 seconds they all quickly show up as registered on the 3cx console when I reboot the 3cx laptop (naturally).

So my question: if I leave the server expires setting to 180 seconds for all phones, will that create any problems for my system or LAN as a practical matter? Since I only have 5 phones I am guessing the LAN traffic is not a real world problem...am I correct? What about phone usability? If I am using a phone when it hits the server expires deadline and re-registers, will that make any sound or otherwise interfere with the phone? And does doing this make it more likely that when I pick up a phone to dial I will (if I do it at just the wrong time when the deadline hits) increase the chances that the phone call doesn't go through?

Thanks.