I've never really used the repeater in 1.2 (I seldom did in 1.1 either), but I've suddenly realised how confusing it's become. In 1.1 it was easy to understand, build it and you can extend the range of the reactor.
I've believed that the function in 1.2 would be the same, albeit it now drains an extra 5 build points. But why does it give you 20 new build points after being built? Nowhere in the description it mentions that.
Sorry for probably being terribly behind, but I've never really investigated this before :p.