To clarify for all.
If you are on DFRDB your benefits are based on the salary you are earning on the day you leave.
If you are on MSBS your benefits are based on final average salary over the last three years.
At the risk of changing the topic I wonder whether it is well known that the govt and tax dept recently changed the bonus payment tax rules for the Pilot Retention Bonus that many still have. A bunch of ex-mil pilots got some legal advice and raised the issue with their local members with success! If you get out before your PRB period has expired you have to pay it back pro rata on the gross amount before tax (ie more than you got). You can now ask the tax department to re-assess your return for the year you received the bonus to decrease your income by the amount you repaid and get a tax refund for that portion repaid.
Regards.