I've updated the cost of "1/8" Single Pane Tempered" from $17.93 per square foot to $12.00 per square foot. This change will be reflected in the glass type dropdown and all cost calculations when this glass type is selected.

I've added the new glass type '1/4" Clear Tempered/ 1/4" Clear Tempered' at $16.00 per square foot to the glass types list. This will appear in the glass type dropdown (sorted alphabetically) and can be selected for cost calculations. The new option represents a dual-pane configuration with 1/4" clear tempered glass on both sides.