I was missing the point that there is a difference between the time one would be using with the tables and what one would log for time under water.
I am just going to expand on this.Don't think of it as what PADI says , think of it as how the DSAT RDP algorithm is designed and applied.
The RDP has the purpose of keeping you from getting bent. It is designed so that your bottom time tells you when to ascend. Your total dive time (counting ascent ) is not important, because if you are not doing a direct ascent to the surface, then you should be counting that extra time as part of your bottom time. The log book was set up in such a way to help you make those calculations.
In modern diving, almost no one is using tables any more, and multi-level diving with computers is not only common, it is the norm. If you are doing a multi-level dive with computers, the old table-based bottom time rules make no sense. Let's say you go to 100 feet because you heard there were garden eels at that depth. You stayed for two minutes and then went to 60 feet for 20 minutes, when gradually and slowly worked your way up to 20 feet. You played around the top of the reef for half an hour. How are you going to log that bottom time? So, for logging dives today, most people are logging their total time under water, which is often called run time.
Summary--bottom time for using tables is one thing; dive time for logging is another.