May I point out, that this calculator had the following three columns...
Corn Sugar, Sucrose and DME.
It suggested for an American Amber Ale (closest I could find to what I have) to add 168.25gm of corn sugar, 153.11gm of sucrose and/or 233.4gm of DME. It doesn't indicate if it's all three, or one of the three. I stupidly read the bottom figure, 233.4gm of DME and assumed that was what I should put in. Ignorant, yes. I didn't even read the DME postfix, just saw a D and went 'Dextrose' woo!