Mark,
This is the only explanation he left;
http://www.subsim.com/radioroom/show...823#post757823
I see that you found his thread over at Ubi; looks like this is going forward and that is excellent news on many fronts.
As far as making TMO compatible with 1.5 Addon here is his quote;
"I think the BIGGEST difference (and im making a WILD guess here) between RFB and TM will be after the Uboat add on is released. There will be fixes to the base game in the add on most assuredly, and it will require some work to get the mods compatible to the base game post uboat add on. (hypothetically speaking sh4 version 1.5).
Here is where the biggest difference will come into play. Im quite sure RFB will be made compatible with it. TM however, will not be. Unless a copy of the uboat add on magically appears on my doorstep, i will not be getting a copy. How can i make compatible to that which i don't own?
I suspect that the addon will contain some stuff that will make it irresistable, which will make the majority of users shift away from sh4 ver 1.4. So under that scenario, RFB will be your only choice in the future. "