Lyneham Lad.
Maybe I can attempt to answer it. It's much like when the government include Nuclear deterrent and pensions in the 2% of GDP figure for the defence budget. You can say you have reduced the timescale to anything you like. It just depends on the level to which your graduate has been trained.
The bottom line is anything is possible. I was CR on the Jag after 4.5 years from the day I joined as a graduate direct entrant. I spent 20 months of that time holding. I would say efficiency is the key.
We can now spend the next 5 pages debating if that's possible or just enjoy our evenings instead and wait and see.
BV