override layout variable in subtheme

For some reason, I can't get my subtheme to override the $layout variable which previously worked in the 1.x version. Here is what I have in my template.php :

function MYTHEME_preprocess_page(&$vars, $hook) {
    
  // determine layout
  // 3 columns
  if ($vars['layout'] == 'both') {
    $vars['left_classes'] = 'col-left span-6';
    $vars['right_classes'] = 'col-right span-6 last';
    $vars['center_classes'] = 'col-center span-12';
    $vars['body_classes'] .= ' col-3 ';
  }

  // 2 columns
  elseif ($vars['layout'] != 'none') {
    // left column & center
    if ($vars['layout'] == 'left') {
      $vars['left_classes'] = 'col-left span-8';
      $vars['center_classes'] = 'col-center span-16 last';
    }
    // right column & center
    elseif ($vars['layout'] == 'right') {
      $vars['right_classes'] = 'col-right span-10 last';
      $vars['center_classes'] = 'col-center span-13 colborder';
    }
    $vars['body_classes'] .= ' col-2 ';
  }
  // 1 column
  else {
    $vars['center_classes'] = 'col-center span-24';
    $vars['body_classes'] .= ' col-1 ';
  }
  
}
// */

I noticed that in the new subtheme template BPSTARTER it doesn't check the layout variable:

  // Variables to change the width of the columns
  // Besure to move the 'last' class name to the correct column.
  $vars['left_classes'] = 'col-left span-6';
  $vars['right_classes'] = 'col-right span-6 last';
  $vars['center_classes'] = 'col-center span-12';
  $vars['body_classes'] .= ' col-3 ';

do I have to do this a different way in the new version?