You may be best off concerning yourself with how much the addition will cost you rather than micromanaging the general contractor's payroll.

Houzz, we need a "love" icon for the comments above.

I don’t think there is anything wrong with comparing or asking this question. That said if you decide to go with the firm who quoted above prices don’t try and knock them down. They’ve told you their costs and you while respect them.

Is there mark up on top (+profit & overhead)?

Field positions have more direct labor overhead costs (significantly higher workers comp, milage, travel, tools, etc.) While local comparisons are best., your numbers look to be about 30-40% above Sacramento region.

@Jeffrey R. Grenz, General Contractor there is a 15% markup (profit and overhead) on material and subcontractor rates, but these project management rates are not marked up.