Mark Hughes in June 2020
https://www.motorsportmagazine.com/arti ... e-trickery
... one of the four new technical directives issued a couple of weeks ago has tightened up further on fuel flow. Now, there are further restrictions on how much fuel can flow on part-throttle. Previously, the permitted flow rose at a specified rate with the revs until reaching its maximum of 100kg/hour at 10,500rpm. Now there is an additional requirement on part-throttle matching the flow to the engine’s power: below 50kW the fuel flow must not exceed 10kg/hour. As power increases, so the flow can increase at the rate determined by a set formula. This should prevent an excess of fuel being delivered at low throttle which could be somehow stored between tank and injectors and used to increase flow at full throttle.
2 FIA documents - 2019 and 2020, we see there maximum volume of fuel outside the survive cell decreased from 2l to 0.25l. Also: "5.10.3 All cars must be fitted with a single fuel flow sensor" - it is in PDF dated 06 march 2020, so I don't think it was an oil that leaks from cooling system, then mixed with air right into combustion chamber or there was something to break flow meter by electric vibrations - it is totally bs. It's so easy to find holes which allows oil to leak or unusual extra electric device to change flow meter data. And that's why FIA didn't changed 5.10.3 part for flow meters in march. (Don't know how it looks in regs now in Jule though)
I think Ferrari gathered some fuel during Qualy into that 2l bottle and simple burned it when they need. Do you remember that slow preparation lap before Qualy lap? It could be only simple something which is in grey area of regulation, Ferrai can used when they want (not as uncontrolled oil leaking ).