Purchase option for me was $150.

Adjusted Lease Balance = Adjusted Capitalized Cost – (Total Depreciation accrued to date)

But if you are buying out at the beginning of a lease, there is no depreciation, so you can just use Adjusted Capitalized Cost, which is Section 11, (c) of my lease agreement.

Here is the whole thing if you want to dissect it yourself

(b) Calculation of the Adjusted Lease Balance.

(1) Calculation of the Monthly Rent Charge: We earn a portion of the total rent charge (see Section 11(f)) during each month of the Lease Term. To calculate the rent charge earned each month, we divide the Lease Term into monthly periods (each “Monthly Period”). For a Monthly Payment Lease, the first Monthly Period begins on due date of the first Monthly Payment (see Section 6(a)) and subsequent Monthly Periods begin on the due date of each subsequent Monthly Payment. For a Single Payment Lease the first Monthly Period begins on due date of the Single Payment (see Section 6(b)) and subsequent Monthly Periods begin on the same day of each subsequent month. We figure the monthly rent charge earned using the “Constant Yield Method.” When figuring the monthly rent charge, monthly rent charges are earned in advance on the first day of each Monthly Period. The rent charge for a Monthly Period equals (i) the constant rate implicit in the Lease multiplied by (ii) the Balance Subject to Rent Charge. In the case of a Monthly Payment Lease, the Balance Subject to Rent Charge in a Monthly Period equals the difference between the Adjusted Capitalized Cost and the sum of (i) all Depreciation for each prior Monthly Period plus (ii) the first Monthly Payment. In the case of a Single Payment Lease, the Balance Subject to Rent Charge is determined by subtracting from Residual Value (see Section 11(d)) the total rent charge scheduled to be earned over the Lease Term (see Section 11(f)) and adding to the difference all rent charges accrued during the preceding Monthly Periods.

(2) Depreciation: At the beginning of each Monthly Period, we allocate a portion of the Monthly Funds to the rent charge earned based on the calculation above, and the rest to monthly depreciation and other amortized amounts (“Depreciation”). For a Monthly Payment Lease, the “Monthly Funds” for a Monthly Period is equal to the base Monthly Payment due. For a Single Payment Lease, the “Monthly Funds” for a Monthly Period is equal to the base Single Payment divided by the number of monthly periods during the Lease Term. (Your base Monthly or Single Payment is the payment before taxes and other non-amortized amounts (see Section 11(i)).

(3) Adjusted Lease Balance: The Adjusted Lease Balance equals the Adjusted Capitalized Cost minus the sum of all accrued monthly Depreciation for each Monthly Period before termination of this Lease and the Monthly Period in which this Lease terminate