In my experience we saw some losses when taken as a system that prevented us from hitting 2:1, but they weren't anywhere near 50%. We also ran closer to 40% than 33% thermal efficiency in the power generating loop, so many of the system thermal costs are baked into that 33% efficiency to the grid.
Basically, each reactor install will have it's own minor issues. Overall they should be hitting around 2:1 as an entire system. If they aren't there is something going on that I haven't come into contact with (which is quite a lot, I'm sure).