This guide has so much wrong I don't really want to write it all.
For example, there is a haste cap and I will share it with you, it depend of your latency though so you will have to find it for yourself, no magical number for everyone.
After you are done casting AM you get a 5 second buff on yourself that give you 12% casting speed, in that time you should be able to cast 3 AB and have time to start casting a 4th AB or AM (depending did one of first 2AB proc AM) because it get buffed with 12 spell cast speed, even if you only cast 0.1sec of that new AB with 0.1second of the 12 spell cast speed buff the whole cast will be boosted. So AB with basic buffs inside the raid should be less than 1.6second cast. Well that's only for ICC mages of course.
Also when you already have 4 AB stacks , you don't go for more AB unless you are blowing CD-s and spamming AB (for crying out loud don't AM when you have APower, unless you are low on mana which mean you didn't prepare for AB spam and full use of Arcane Power) when you have 4 AB even if you have enough mana you don't continue AB-ing , its not WORTH IT! You will go oom and become useless before you blink in reality .
And you DON'T! Presence of Mind if you don't have 3 or 4 stacks of AB! (I Recommend 4 if you have some boost on top of POM) you get 30% bonus crit when you use Presence of mind!
I just don't understand how do some people give themselves the right to teach people how to play a class when they are lacking the basics.