So now that invisible chapter choices have been implemented I'm looking at writing a gamemode story again, but I was unable to have a characters "daily pay" variable and add this to a bank balance. It'd be great if rather than adding/subtracting/setting fixed values to variables, you were able to use another variable as the amount to change a variable by. This would mean the character would be able to get a better paying job and earn more money. I guess I could do it with multiple different chapters, one for each pay grade, but that's a hideous workaround.
This is a planed feature for the formula parser, which wont be implemented until well after the rollout of CHYOA 3.0...
Yes, using more than one variable would be a great addition. Like Nemo stated, there is a related suggestion Formula Parser which would allow that kind of calculations.