Practice will resolve this.
Erm ........ sorry, although you learned this on a DIR course it is nothing new. If it would help, I have a little spreadsheet I created to help with gas planning ........ if interested then PM me an email address. One page will help you calculate your current SAC. The other page plans your gas usage on a dive using that SAC. It is really only for square profile dives - you can use it on for other dives but you need to break the profile down into a number of square profiles.
Once again, is that not your attitude that was at fault rather than a failing in any training agency. Once you learn the basics you should still be continuing to learn and improve. Also, I'm not sure they aren't covered in other agencies' courses (it has been MANY years since I did my courses)?
The crux of the matter - please elaborate on these unsafe practices.
Once again ...... this should be the norm although, IMO, the importance becomes more crucial with depth or difficult conditions. A dive to 10 mtrs in warm conditions doesn't NEED such critical planning. Also, for example, you are diving on a new (to you) wreck. What are your goals going to be when diving something you have never seen. In my patch the vis may vary enormously which drastically affects what is done on the dive.
And will only be of interest to fellow DIR divers.
Once again this is not a DIR invention.
Here I do disagree. OK, if you are hanging on a deco stop then by all means practice to your hearts content. Surely you should be practiced before doing the dive ... and in a safe environment like a pool or ..........
Also, I don't know what diving you do but .......... for me it is about £35 to £45 for a charter boat. Gas is about £12 for the twins + say up to £10 for my deco mix. Take into account the time getting to and from etc etc and I am not going to be wasting five minutes out of a 30 minute dive practicing drills. If I don't already know it and might need it then I shouldn't be doing the dive.
In your opinion. The PADI courses teach you the basics which get you in the water. You then acquire experience and further knowledge as you progress.
I am pleased for you and your DIR passion but don't expect everyone to agree with you. I hope you never confuse any of your many hand signals and that your reverse finning techniques become so proficient that you require a flashing light and a beeping thing to warn others that you are about to reverse.