The GC compares the sub bids again, this time with more care. It holds scope review meetings and then writes the subcontracts.
A sub that was low on bid day is not yet hired. The GC may ask you to confirm scope, schedule, addenda and price.
Come to the meeting with your takeoff and proposal. Confirm what you included. Do not agree to new scope without a price for it.
Read the subcontract against your proposal before you sign. Make sure your exclusions and qualifications carried over.