Okay so my strength is 4. My bonuses are +20%, + 25%, +10% which should give a final of 55% or an effective strength of 6.2.
The strength of the elephant is 8. It has a 75% terrain bonus which should give it a strength of 14.
So the odds are really 6.2 vs 14.
Not 10.00 vs 4.21 95.5% for me!!!
Aside from the nonexistent defensive terrain bonus (already pointed out by someone else) you're also forgetting the Hunter's natural +50% vs animals bonus. This matchup should actually be VERY close (with the Hunter having the slight advantage.)