Catering Service Charge Costs

My fiance and I recently had our first catering consultation. It went very well - the business owner was extremely nice and they have received fantastic reviews on all websites. The food menu we picked sounded amazing and it even came in under our budget (~$1200, our budget is $1500-$2000. We are serving approximately 75 guests the day of. My problem is that the service charge for a captain, bartender, and servers came in on the proposal around $1100. I knew/was expecting the service charge, but not at almost the same cost of the food, plus we still have to consider a tip at the end of the evening. We were told that we would be paying for the event hours and the time it takes for the staff to return to their headquarters and clean/unload everything. Is this usual? I am disappointed that the service charge may be the deciding factor. The total cost including taxes & upgrades (coffee, $100 for 50 guests, and upgrading from their included plasticware to nicer plastic for $55) is $3100.