Problems with 2nd DHCP IP address - bridged mode

Hi there. Recently switched from the Broadband 100 to Wide Open 150 and overall I am happy with the speed and reliability. My primary home network is very stable, and my wifi router always gets the same IP address, even after switching from the Cisco to the Hitron modem. It has been the same address for literally years, which is very handy. The problem I am having it trying to get the second address to work. I've talked to support a couple of times and they don't know what the problem is. The configuration for the second IP is there, but actually getting that second address is extremely unreliable and does not work most of the time. I've used a laptop and two different routers for testing, we have taken the modem out of and returned it to bridge mode and done numerous modem reloads. I did manage to get a dynamic IP on my laptop recently (a 50.xxx.xxx.xxx address on a different segment from the primary), but it would not return after I disconnected and reconnected. Same deal with one of the two routers (which got a 24.xx.xx.xx address), but would not return after a router reload. Again today nothing seems to work. DHCP broadcasts are going out, and nothing is coming back - I've verified this with both debug mode on one of the routers (Cisco 871) and with a Wireshark capture using both a span port on my switch and running directly on the laptop. I've tried different ports on the back of the modem as well as trying both routers on the same modem port through a switch. I've even tried cloning successful MACs in case they are cached by the server, but no luck with that either. The first one always comes back with out issue (thankfully) but it just does not want to hand out a second IP. Anyone else have this problem, or any ideas on anything I could try to resolve the issue? The support people are helpful, but obviously don't have any visibility into the DHCP susbsystem. Is there any way to escalate this to someone who can actually look at a packet trace and track down the issue? It is not critical, but I really would like to get this to work reliably. Any thoughts or ideas are appreciated. Cheers