Lease -sale and leaseback

I have listened to a lecture on sale and leaseback, I tried not to miss anything but I have a question.
In BPP Kit #157 there is a following text:

Tourmalet sold an item of plant for $50 million on 1 April 20X4. The plant had a carrying amount of $40
million at the date of sale, which was charged to cost of sales. On the same date, Tourmalet entered into an
agreement to lease back the plant for the next five years (being the estimated remaining life of the plant) at a
cost of $14 million per annum payable annually in arrears. An arrangement of this type is normally deemed to
have a financing cost of 10% per annum.
What amount will be shown as income from this transaction in the statement of profit or loss for the year
ended 30 September 20X4?

I solved it in a way given in your example:

Proceeds Bank DR 50000000
Derecognize asset Plant CR 40000000
Liability @ PV Plant CR 53071015 (w)
Right of use Plant DR 42456812
TOTAL 92456812 93071015
SPL DR loss 614203

(w) 14000000*annuity factor=14000000*3.7908=53071015
annuity factor= (1-((1.1)in power minus 5))\0.1
annuity factor= 3.7908

But BPP gives absolutely different way, asset is recognized at 50 mln fair value, the same amount liability is, $10 mln difference is then treated as deferred income over the life of the asset. 10 000 \ 5 years * 6\12 = 1 mln gain

Does this way refer to old IAS 17 and we don’t use this method any more ?