SASS $tab-base-color-over does not seem to be applied

[zontal]

I am using SASS to try and control the color of the text and background of tabs. I have the following in a my SASS file as a test:
.
.
.
$tab-color: black;
$tab-color-over: red;
$tab-color-active: white;


$tab-base-color: green;
$tab-base-color-over: red;
$tab-base-color-active: blue;

Everything seems to work great except for the $tab-base-color-over...I cannot seem to change the background color of the tabs on a mouseover. What am I missing? Thank you very much for any ideas....

[zontal]

Let me try this...has anyone successfully used any of the following SASS variables:

$tab-base-color-over
$tab-background-over
$tab-background-gradient-over

??