Speaking purely about theory, I seem to recall from previous posts that fast tissues like blood only take 2-3 minutes to saturate, and since the process is exponential, even one minute at depth gets you most of the way there. Also as Thal pointed out, Doppler studies have showed bubbling on just about any dive. IIRC, other Doppler studies have also found that the maximum number of detectable bubbles seems to be about 50 (to 60?) minutes after surfacing. However, I don't know how true this might be if someone hasn't been under pressure long enough for tissues other than blood to pick up significant amounts of oxygen. Nevertheless, if the former is true, all this might suggest that even with a short dive, an SI of 60+ minutes might be a good precaution. OTOH, if other tissues really aren't offgassing into the blood stream, maybe only 5-6 half times for the blood alone (15-20 minutes?) might be needed. Either way, I'm wondering if after a bounce, even if it's the first dive of the day, a decent SI afterwords might not be a bad idea.
If the half-time of blood is 2-3 minutes as far as ongassing that's also the half-time for offgassing so that isn't really an issue.