Just wanted to give an update as to where I am and what I did.
While the XTB-IIR did indeed fix my flooding problem and gave x10 plc reliability at the same time, I was back to the same quirks of AHP. By quirks I mean the need to use phantom modules for security devices if I wanted to use conditions and problems with flags sometimes not being set. Using phantom modules also meant an extra second or 2 before a light would turn on.
So I took the plunge and also purchased HCA 12 Plus. HCA is Home Control Assistant. I also got the WGL W800USB. So now I have the W800 receiving all RF signals from remotes and security devices including security remotes and they go directly in to my computer. For X10 plc I'm using a CM11a. I can now use a DS10A to trigger my porch light to turn on when I open the door and it actually turns on before I step outside, about 1 second later. Before with AHP and phantom modules it took 3 to 4 seconds.
What I really like about this setup is the fact that X10 RF signals are not directly broadcasted over the powerline by default. I can tell HCA to automatically retransmit the RF to PLC by house code, or I can setup programs for each HC/UC one by one. More work to setup but it keeps the powerline free of unnecessary PLC transmissions. So now my motion sensors not only trn on lights at the times I want, the PLC from these motion sensors do not clutter the powerline on the other times I do not want the light on.
This is a very powerful solution if anyone is looking to move on from AHP. I wasn't looking but when Joe S. mentioned his setup earlier and I looked in to it, I jumped. So thanks Joe.
Also, if interested Smarthome has the HCA12 Plus for $120 while direct from HCA it's $160. You have to wait for the CD to be mailed, but the $40 savings was worth the wait.