That's really weird... I think you don't need to change anything more than that but I don't get it, I download the pack to check the default settings (I have a copy of the modpack, of course, but I wanted to check this by the FTB launcher) and it was false... I don't understand why yours came set as true... Really odd...Odd - mine says 'true'. And I know I haven't accessed the configuration screen until you asked me to check.
EDIT: Looking further through the Agricraft options, it looks like everything is set to the default. My personal outlook is that I play modpacks the way that the creator intended, so if there are any other 'non-default' values that you've set, I'd be more than happy to correct them.