The following is not presented as a didactic in staged decompression diving... this is presented to show you that your recreational computer is not up to the task of decompression diving and should never be intentionally taken into deco mode.
Darryl re-reading your initial post I realize that I gave too quick a response without enough information and explanation.
Your computer neither allows nor disallows you to do anything... it merely presents information and you decide how to use that information.
A conservative computer used unthinkingly is not safer than a liberal computer used with understanding.
Now as for the issue of deco stops. Liberal computers include them as well, even though all owners manuals I have seen to date include warnings and disclaimers. For instance the bold type warnings in the Savant manual seem to appear every other paragraph warning users not to go into decompression mode. The deco mode merely exist to accomodate the accidental violation (and IMO it is also a concession to marketing.)
One of the problems with deco stops as given by dive computers is that they start with shallow stops and then only add deeper stops as the violation becomes more egregious. A diver trained in deco diving knows that every dive is really a deco dive and always includes the minimum deco of 1@30 1@20 1@10... rather than the 3@15 that your conservative computers call for. As the dive gets further into the realm of staged decompression and real deco obligations begin to accrue, extra time is added to the shallow stops but deeper stops are added as well. These deeper stops are very important to keep bubbles from forming in the first place. Unfortunately for the poor (and irresponsible) recreational computer diver who takes his computer into serious violation these extra deep stops are not added automatically. And bubbles once formed at depth are not going to easily relinquish their nitrogen with extra time at shallow stops. In fact there is evidence that it is easier for gas to enter already formed bubbles than to exit in solution through the blood & lungs. So the bubbles once formed tend to grow.
Now the reason I took the time to give this little generalized background is to answer your question above:
<<<It does not make sense to have a conservative computer that goes into deco mode, and then follow its directions.>>>
It was not designed to nor can it give you good directions on how to deco out.
And to answer the last question:
Deco stops are not always benign... longer time spent in deco can be hazardous and the goal should always be to reduce the deco time required by careful planning and execution of the dive (including using appropriate deco gases.)
This is not the technical forum and this is not presented as a didactic in staged decompression diving... this is presented to show you that your recreational computer is not up to the task of decompression diving and should never be intentionally taken into deco mode.
