One Thing: If the +50 Level AI Upgrades do not raise the price of the levels, they are not strategic, all they do is add the number to your levels. They were strategic, if they would save you the cost of the next 50 levels, forcing you to buy them as late as possible to generate the highest value.
the angels are calculated with your overall earnings OE, following a squareroot function, meaning AIs are proportional to sqrt(OE). This means that AI are getting more "expensive" with every dollar you earn.
its pretty frustrating in lvl 34 to first dominate the map, then the black ai comes out of nowhere, with ships twice as fast as yours, and they just wipe you from the map. Is there a special trick to beat this?