The way I solved it, which was surprisingly easy, was by having a few batboxes like this:I believe one cycle costs 800 EU, not 625, so that might be your mistake.
And the not wasting energy advantage is still true, you just gotta keep your generator from overproducing. Use it to charge the batbox when it's empty, and not to provide power for machines.
Geothermal generators, by the way, only produce on-demand and will never waste EU. All other sources however (including nuclear reactors) will happy run regardless of whether or not there's a place to put their energy.
Code:
(G)(B1)(B2)(B3)(B4)(M)
C R R
(B1) set to "Don't output energy when having redstone signal, (B2) set to "Output redstone signal when full" and (B3) set to "Output redstone signal when empty". R is redstone and C is the computer.
Then I just made a simple t-flipflop script on the computer (even someone as programming illiterate as I found it easy with an internet reference) so that when it gets redstone from right side it switches between on/off redstone towards (B1).