I think you may be setting the variables too late in your SCSS file. The heights in the keyframes should include both variables, $v-loading-indicator-bar-height as well as $v-loading-indicator-bar-height–wait, and I don’t see “35px” anywhere in the keyframes in your post.
Can you confirm that you are setting them in your theme’s scss file before the theme mixin definition? For example:
@import "../valo/valo.scss";
// SCSS Variable assignments go here
$v-loading-indicator-bar-height: 35px;
$v-loading-indicator-bar-height--wait: 35px;
@mixin mytheme {
@include valo;
// Other stuff goes here
}