Bitrate isn't the be-all and end-all. I also don't know what the percentages on your VBR examples mean.

What encoder were you using? And other tweak options, filters, etc?

I've personally done my entire collection with LAME 3.90 alpha 7 and r3mix settings minus the normalizing and a minimum bitrate of 112kbit (instead of 96). The average bitrate per song goes anywhere from 160kbit to 240kbit. This is my accepted best all-around compromise for space and quality, without spending the time to make optimal settings on a per-track basis.

Bruno