Crits are much less important for ranged attacks than melee hits, only increasing pDIF by 25%. Also, the effect isn't capped so ranged critical hits represent the same % increase in damage regardless what your cRatio is.

You can probably call Last Stand 4.5 fTP as well, because of the TP Bonus Moonshade. So it's more like 1.3x fTP and some crits (damage +25%) vs. 1.66x Mod. Factor in that DEX is probably less convenient to whore than AGI, gun/bullet's higher base damage to start with, and you see why people like Last Stand.
Gandiva + Garg = 117 + 51 = 168
Anni + Adaman = 76 + 127 = 203

fSTR caps higher with Gandiva, but not 35 points higher.