When it starts working, you get a dialogue from old thomas saying oh go look etc. At that point the times displayed in exchange show the new value: so the eggs and milk exchange (usually 2 hours) shows as 1 hour.
Not being patronizing just saying what signs you should check for. I hope you don't have to uninstall/reinstall to get the effect.
Edit: SW posted 1 min before I hit enter, lol.