I have autofilled to 6 Stamina gems.
The Stat Summary shows the item with 195.7 Health for 19 Stamina (19stam + 3% from talent = 195.7 Health).
It should be 31 Stamina when adding the 2 6 Stamina gems and showing 319.3 Health.

I may be wrong on how that addon is supposed to work too, not sure. Cannot test with an item with a gem equipped since i'm not on beta.

Thanks a lot for reviving the addon by the way. Definately a must have for fine tuning around that 102.4%.