Not really; unless the organic armor gets hit before the crystalline, you don't get the organic bonus.
Plus, you're decreasing your crystalline total, which is almost never "enough"
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Now, if you were to mod the organic armor to be 1/6th in every stat (size, regen, hitpoints) then it would be a totally awesome combo.
The mini-OA gets hit first almost always, and regens, while the CA keeps the shields pumped.