@Dr-GO
Wow, I'm impressed by the salesmanship that gets venues to sign this EBQ contract.
It does not designate length of performance (set lengths, number of sets, end time, or any other elements that would allow determining this). By signing, the buyer explicitly agrees that they receive the services to which they are entitled - obviously well in advance of actual delivery (if). The venue has no recourse for damages in the event illness prevents EBQ from performing - most I have known want the equal of the deposit they pay up front (in addition to that refund) as damages (of course, the odd format of Section 8 shows that while deposit used to be part of this, there is none - an unusual risk for the ensemble).
Says a lot about the excellent reputation of the group that it can book under these terms.