Yeah, I noticed what curtis pointed out earlier, too. However, you strike me as someone who would be aware of optimal positioning. I figured the placement was due to WAF or to keep the cabinet away from itty-bitty curious fingers.
This hobby of ours, nay, obsession must be handled delicately regarding spouse approval. It really comes down to compromise and open-mindedness. I agree that your wife is very cool to afford you the liberty of these purchases.
There are not too many other options for your center placement, other than mounting above the TV, moving to inside the cabinet (which opens another can of worms), or simply pulling it forward to the edge. Honestly, it's probably best where it is (vertically speaking) considering the tweeters are approximately the same height.
Out of curiosity, does your wife prefer the gloss finish on the Sierra-1 center or the satin finish on the Towers?