[Ironfist]

The ratio depends on the battle type

1. Defend -- 2.5
2. Delay -- 2
3. meeting -- 1
4. advance -- 0.5
5. assault -- 0.4

That is, if you set human to be 1250 points and you actually spend all of them, plus 750 points on supporting troops, which makes your total troop worth of 2000 points, AI will have:
1. 5000 if YOUR mission is defend
2. 4000 for delay
3. 2000 for meeting
4. 1000 for advance
5. 800 for assault

What really matters is the points you ACTUALLY SPEND. That battle points option only limit the maximum points allowed for your core force in the beginning. You can set it to a bigger value, say 3000. If you only spend 2000, then ONLY 2000 will be counted for AI to buy its troop.

And when your core troops gain experience and become more valuable, you will face more AI units.