sale and lease back

Hi Sir, may i ask a question regarding to the measurement of right of use asset retained through the sale and lease back when the proceeds are less than the fair value of the asset.

I understand that the amount below fair value is treated as a prepayment of lease payment. In this case, can I calculate the proportion retained as: ((fair value – proceeds) + PV of lease payments) / fair value? because the amount of (fair value -proceeds) also forms part of lease payment.

If the asset is sold more than its fair value, the excess is treated as additional financing. Can I calculate the retained proportion as: (PV of lease payments – (proceeds – fair value))/fair value? because the amount for additional financing is not part of lease payments?

Thank you 😉