What are the deposits for an exclusive use contract?

Non-Refundable Retainer deposit to hold the retreat week is $4000:
1st Payment: $2000 To be paid upon signing of contract.
2nd Payment: $2000 Due 1 month after signing the contract.
3rd PAYMENT: $5000 Due 4 months before the start of the retreat
FINAL BALANCE PAYMENT: To be paid 60 days before the retreat starts.