this one is the only double that has less min/max dmg then tripple so better use explosive triple

Personally I think this Double is little bit better compared to Explosive Triple. With enough nano initiative this can be casted in 1s and recharge is 4s, this makes it 5 second cycle while Triple has 2s + 6s = 8 second cycle (and 2s is harder to cap because it would be 5,5s reduction from 7,5s and this has 4s reduction from 5s). So, during 40 seconds it is possible to cast this 8 times and Triple 5 times (40/5 = 8 & 40/8 = 5), this means 8x 2x 417-696 = 6672-11136 damage in 40 seconds and Triple would be 5x 3x 445-742 = 6675-11130 damage in 40 seconds.
Yes, Triple does have higher min dmg but also lower max dmg. Huge benefit that Double has over Triple is 1 second cast time compared to 2 second cast time (less time to get interrupted during casting for example) and also lower recharge time.
Benefit that Triple has in PvP is that it has better chance to do more damage on target than Double has (there is 50% rule and 30% rule so if target gets hit by 30% of max damage then Double can do up to 2x 30% = 60% and Triple can do up to 3x 30% = 90% dmg of target's max health in PvP). I don't PvP much but at least I believe it goes that way..
If we check dps for both of those with capped times then these would be 166.8-278.4 for Double and 166.875-278.25 for Triple.