The second question's simple: Maximum increases the maximum amount you can store; Amount means you can use the component (it will appear at the bottom of the main screen in a nice row) to instantly replenish that much. (So Shield Generators have the Shields Maximum effect, while Emergency Shield Capacitors have the Shields Amount effect.)
As for the first, perhaps you forgot to increase the Number of Effects field, which comes right before the list of effects? If that doesn't fix it, let me see your data files; SJ did what you're trying to do in his P&N-ism mod, so it IS possible
