Did the flattener help against weak bots?

Well, firing waves at every bullet power you might use is very similar to PIF... However, notice that they could be indirectly reacting to fire power by doing something like changing directions randomly every time a bullet is fired (and bullets are fired more frequently at lower powers). If a robot just had a threshold for changing direction and evaluated that every turn, regardless of bullet fire, I would expect firing multiple bullets at different powers to be effective, but probably not worth the extra CPU.