Lease adjusted leverage (Pre-IFRS 16)

Hi,

Can somebody please clarify the methodology of how operating leases were capitalised prior to the introduction of IFRS 16? (for the purposes of calculating rent-adjusted leverage)

I have read that a rule of thumb was 8.0x rent expense added onto net debt / EBITDAR. Whilst I understand it differs by industry, is anyone able to provide colour on how that multiple is determined? (I.e. is it based on weighted average lease term remaining?)

Thanks in advance.