But I agree that is not a big deal, since this scenario is hard to have.
There will always be cases that defeat the load-balancing algorithm. You could probably fix that particular case by doing tricks similar to one I described in the other email for big.LITTLE. However, you risk introducing new cases of undesirable behaviour.
An even easier fix for this particular problem is to just go back and use the static load.weight for load-balancing. :)
That's impossible.
And I have no idea to let task update load_contrib instant. Maybe close eyes and wait for 2*sched_period time is the best thing we can do. ;)