You have normal FTLs then you have variations then you have LRV (Long Range Variation)
LRV MUST be of a higher standard or equivalent to normal FTLs they can not be of less standard.
Normal 3 man crew can go max 18 hours duty however as that is all-ready a variation you can not have further extension.
If by some chance you do go over the 18 hours Duty then a local nights rest is a requirement.
Incorrect of the company to state that your 900 limit is based on Stick time. Absolute fairy dust
If you are one of those pilots flying over 900 BLOCK hours in 12 months at the end of the previous month you are not legal, period.
Emirates have a lot of issues they are not admitting to. Flying pilots over 900 Block hours and saying stick time applies instead is yet another.
Check CAR-OPS 1 sub section Q copied below
CAR-OPS 1.1125 Absolute Limits on Flying Time and Duty Period
a. No person shall act as an operating crew member of the flight crew of an aircraft if at the beginning of the flight the aggregate of all his previous flight times;
(1) during the period of 28 (twenty eight) consecutive days expiring at the end of the day on which the flight begins exceeds 100 (one hundred) block hours: or
(2) during the period of 12 (twelve months) expiring at the end of the previous month exceeds 900 (nine hundred) block hours: