Hi, leapfrog. I have both PADI and Buhlmann dive tables.
I was surprised by your statement that
A safety stop at 3 meters for 3 minutes at the end of every dive was what I was taught by my instructor.
I always tell my students that everything they need to know about the RDP is on the tables (i.e. on one side or the oher) themselves. The PADI recreational dive planner tables have some
"fine print" on the backside.
That's important stuff and not to be ignored, ever.
Safety stops --
the optional 3-minute safety stop at 5 meters/ 15 feet becomes mandatory if you get within three pressure groups of a no-decompression limit, or for any dive deeper than a hundred feet.
Emergency Decompression -- If for some reason you exceed a no decompression limit by up to five minutes, you must make an 8-minute decompression stop at
5 meters/15 feet, and then not dive for six hours. If the no decompression limit is exceeded by more than five minutes, you must make a 15-minute stop at
5 meters/15 feet and then not dive for at least 24 hours.
So I think you should talk to your instructor to find out why he said 3 minutes at 3 meters.
You mention you also have "Buhlmann tables". Buhlmann Sea Level Tables, Buhlmann Altitude Tables, Buhlmann Sea Level Tables with Deep Stops...? Who gave you, taught you and recommended the Buhlmann table(s) and what for?
All dive tables do essentially the same thing, just not exactly the same way (and often with surprisingly different results). For example, NAUI tables are a bit different from the PADI tables, and they use different definitions and acronyms -- just enough to throw you off. It's like driving a car where the gas is on the left and the brake on the right, and one calls the gas "accelerator" and the other "velocity increasing accentuator".
For recreational diving, use and understand one set of tables and stick with them.
For further information, as usual Scubaboard is an excellent source, you can take a look at this thread:
Safety stop at 15'..........always [Archive] - ScubaBoard