I think most exponential backoff schemes I've looked at treat the 'backoff delay' as a range and do randrange(0, current_backoff) or similar which does what you

I think most exponential backoff schemes I've looked at treat the 'backoff delay' as a range and do randrange(0, current_backoff) or similar which does what you say. Truncated exponential (where you cap the upper limit of the retry delay to some maximum) is also often a good idea, to prevent a short service outage from spiking the retry timers to crazy numbers.