Most likely you're referring to the fact that it calls eatdrink twice (initially above, overdrink below) and eatdrink delays on a 3 second between steps, normally... That means that it can take several minutes to run properly, especially if you have a lot of items. Also, it overdrinks at the end... I've commented out both steps. Here's the version of castle_farming.ash I'm using now. It's based on Xenthes' original script, but with a few tweaks... mainly, it skips EatDrink (though it's still imported, if you choose to just remove the // commenting it out), doesn't sell any thin black candles (because they're fun for demon summoning), and keeps one of each of the sold items in inventory, so if you actually want to use a rave whistle as a moxie plinker, you won't find it suddenly disappearing on you.
You can see if this works for you... your problem bits (the EatDrink) shouldn't affect you with this copy. Or just comment out EatDrink, top and bottom...