Not in the slightest scripted or anything of the like. The battles run from the same RNG, same server etc. as the real games. You could call it fun mode because that is what the money balance in battles actually is.
What I meant with bulk batches is that they buy e.g. 1,000 10-man battles at 0.10 with 25 spins for 10 players with prizes 6, 5, 4 FS. That costs money that the game provider is charging to VS. Hence, if they buy let's say 10,000 battles, they most probably get a better price. These are just random amounts, no clue what the real numbers are.
Also, maybe NetEnt or Thunderkick battles are cheaper to run because they require less bandwidth when over 1,000 players are hammering the games at the same time. AFAIK, bandwidth is one of the main cost factors when running a casino.