Your math is wrong. SEP assumes a value of strength=1 where the secondary stat is relative to 1, greater meaning its worth more than one strength. So if simcraft shows strength being 3.51 and crit being 3.11 the SEP of crit is .89. Askmrobot shows a SEP for crit of .73.
I'm not sure where you get the 1.8x2 value either. If you're trying to do the whole "gem if the SEP of the secondary stat is greater than .5" NO DUH. That isn't the point. The point is if you have a bad SEP for crit, you're going to be meeting socket bonuses when you shouldn't be. Example. Mastery has a SEP of around .63 If by gemming hit/crit you can get at least 160 mastery from another piece of gear via reforging (since you no longer need that hit to cap) than you can substitute hit's value for masteries when deciding if a socket bonus is worth meeting. So (160x.63)+(160x.89)+(socket bonus-normally 60 str)=100.8+142.4+60=303.2 SEP. Gemming pure crit and ignoring socket is 320x.89=291.2. In this case, gemming crit isn't as good on the surface.
There are two caveats though, and a note. Personally, when I tested to see if I could use hit/crit gems, I ended up gaining 120 strength and 200 mastery, at the cost of 320 crit. Not worth it. First, at higher gear levels, the chance of being able to exchange 160 hit for at least 160 mastery and still arrive at hit cap decrease greatly, especially with Feather. So any point you don't get in mastery either has a lower SEP because it went somewhere else (haste) or because it's going towards overcapping hit, which has a SEP of around .42. Secondly, if the socket is red, and the only other option is 80 strength 160 crit, than AMRs undervalued crit will show str/crit being the better gem. Again, the problem is 160 mastery is better than 80 strength. So 80+60+(160x.89)=282.4.
Lastly, let's just check what other warriors are doing- and not just any warriors. You can see where they are meeting sockets and where they are ignoring. These are all warriors I know personally or else are known for being incredible theorycrafters, or are at the very least good players.
http://us.battle.net/wow/en/characte...alopy/advanced
http://us.battle.net/wow/en/characte...ision/advanced
http://us.battle.net/wow/en/characte...dsoul/advanced
http://us.battle.net/wow/en/characte.../Tact/advanced
http://us.battle.net/wow/en/characte...Varri/advanced
http://us.battle.net/wow/en/characte...ighty/advanced
Landsoul has been doing that for a while now. It's not better (generally speaking), but I haven't asked him yet why he still has it. I'll try and find out. Also, his high amounts of haste are simply incidental- there is a lot of haste on his gear, he isn't gemming/reforging into it.