Top of your page, the only way to get 363 sp from Bell, is
2178*20
120
Instead, you should use a 97s Interval for this trinket (simC used 106.9, not sure why), most cases it has a 20.6% uptime. I've been using Mirror as a 115s Interval (simC uses 112), as in most cases it has a 17.3% uptime.
However, after reading further into this, SimC stat weights are much different from mine.
Ive been using these stat weights;
Int 3.54 Sp 2.55 Hit 2.66 Crit 2.155 Haste1.375 Mast1.37
Which would put
Bell at 1927
Mirror at 1865
Seems like SimC's numbers change on a daily basis, even tho its simulated stats dont, but since SimC seems to be the accepted method of determining DPS, I can't be the odd one out. Using their numbers
Int 3.3055 Sp 2.4683 Hit 2.4494 Crit 1.4769 Haste 1.4553 Mast 1.2501
As you can tell by the numbers above, this is even extremely different from the stats listed on pg5, where I came up with the list.
This would however put
Bell at 1644
Mirror at 1722
By yours and my own standards, and until stat weights change again (maybe tomorrow!) mirror is the better trinket in SimC.