Well mine was backed by actual data as well. Aside from my personal observations and logs, it's quite simple, lets take a boss hitting you once per second over 100 seconds, so 100 hits. Let's say I have a 33% chance to shield, that means I get 33 heat screens from that. I also get rocket punch on cooldown every 7.5 seconds, that's another 13 screens. Now add the 15% chance from other attacks (about 66 GCDs minus the 13 from rocket punch in 100 seconds), that gives us 7 more stacks for a total of 53 screens in 100 seconds. That gives almost an average of a screen every 2 seconds, it rounds to 1.9 seconds. Again this is the average, this isn't minimum or maximum. What there is though is a 1.5 second cooldown, which means on "average" you will get a screen every 3.4 seconds. Using that average I can calculate 0 screens for 3.4 seconds, 1 screen from that to 6.8 seconds, 2 screens from that to 10.2 seconds, and 3 for the rest.

I agree with you that everything depends on cooldowns, shield chance, and even how many mobs you have on you. And for the purpose of boss gearing that this thread is all about we're not talking into account said cooldowns, and we certainly don't have 9 mobs beating on us like the the video you linked me to trigger an enormous amount of shields. While it is completely possible to get it as low as 9 seconds we are talking averages here. Also in a fight like Dashroode where there are tank swaps, it's unfair to discount the time it took to build up screens during the swap. it seems like people on the thread started counting at the first blast.

See if I was to go by my 12 second average in 96 seconds, I would blast 8 times. But if I started counting my first blast at 0, that means I would blast 9 times...that gives an average of 10.66, pretty much the 10.7 people were saying that tank was averaging...because they didn't count times he wasn't tanking. That doesn't give you true numbers. We run stuff without tank swaps, so I am getting beat all the time and my personal best is a blast every 12 seconds on average. Even the guy that posted torparse of his HM fights said he had heat blast up 47% of the time...which is pretty close to the 50% that a 6 second effect every 12 seconds would be. I don't see any data that supports 20.5%, in fact I would go as far as saying that 20.5 is completely impossible. Assuming you magically started with the +3% absorb from three stacks of screens (which is impossible on its own) that brings us to 17.5% from the actual blast part. With a 1.5 second cooldown on a screen, you can get 6 stacks in 9 seconds, and 15 second cooldown - 6 stacks = 9 second cooldown...meaning 9 seconds the absolute minimum. at 9 seconds that brings you to 16.67%. Now if that happened, you would be at 0 stacks for 1.5 seconds, 1.5-3.0 you would be at 1 stack, 3.0-4.5 you would be at 2 stacks, 4.5-9 you would be at 3 stacks. Do the math, that averages 2% over the 9 seconds. So at BEST, the maximum absorb you can get from blast/screens is 18.67%(16.67 from blast + 2% average from screens). To get 17.5% you would need to get a blast every 8.5 seconds, which means you would have an uptime of 70.5% of the time as well as circumventing the internal cooldown. I challenge you to find me a log that has a blast uptime over 70%.