First, what is the real risk? It is not DCS, it is CNS toxicity. The risk of pulmonary toxicity is also an issue more so than DCS. 

Repetitive diving needs to be done with this in mind. You do not want to run high ppo2s over and over, and you certainly do not want to do multiday diving on high ppo2s. So the first thing we need to do is back off the working ppo2, and plan the decompressions such that we are not accumulating an excess exposure. 

If you do you decompression the way I outlined it in the other posts, including the way I ascend to the surface, you will greatly reduce the heavy bubble-form offgasing that generally occurs post-dive. If you are basically clean, you can dive again without penalty. If you are using the correct gas, the "residual" effect is greatly reduced. This effect is more designed to explain accumulation of gases in tissues which are not well perfused and as such tend to trap gas which becomes a battery for supplying gas to formed bubbles later on, so repetitive diving with a gut, or battery which holds gas, could contribute to making any bubbles on the next dive worse and contribute to them growing well after the dive. 

This does not apply to most of us. 

If you do the decompression for the subsequent dives correctly, there is no reason to belabor the issue. 

From a logistical standpoint in the ocean, it is far safer to do a couple of back to backs than one long dive which requires a long mandatory decompression. 

From a decompression point of view, we have seen that repetitive diving makes no difference, so we ignore the first dive in calculating the second. The only trick is that the second dive should be deeper than or equal to the first, and you can not bounce dive after a dive of any kind. We have done back to back 300's with 60 minute bottom times with no change of deco schedule. In the WKPP we have discontinued that practice due to the oxygen exposure risk, however.