How does leave accrual work when taking terminal leave through the end of orders?

I’m on active-duty orders through Sep 30 and I’m trying to determine my last actual duty day before taking leave through the end of my orders.

My most recent LES (generated Aug 14) shows:

• BF BAL: 22.0
• ERND: 1.5
• USED: 0
• CR BAL: 23.5
• ETS BAL: blank

My understanding is that I should finish August with 24.5 days accrued.

What I’m confused about is September. Since my orders run through Sep 30, I should earn another 2.5 days during September, for a total of 27 days earned by the end of my orders.

Can those 2.5 September days be included when determining how early I can start terminal leave, even though they haven't actually accrued yet when the leave begins?

For example, if I start leave on 4 September and remain on leave through 30 September, that's 27 calendar days. I would only have 24.5 accrued going into September, but would earn the remaining 2.5 while on leave because I'm still on active-duty orders.

Would 4 September therefore be a valid first day of leave, making 3 September my last duty day? Or can I only start terminal leave based on the leave balance I've actually accrued as of the day the leave begins?

Basically, I'm trying to understand whether projected leave earned while on terminal leave can be used to extend terminal leave through the final day of orders.