I will also choose FRS in RA and keep remaining in OA/SA for liquidity sake.
It's SA/OA, actually. OA cannot be withdrawn until SA is. You have liquidity with OA repayments, but the price of that liquidity is quite high. You have to tap the 4.0% interest earning dollars first, before you can tap the 2.5% interest earning dollars.
There are obviously different ways to play this game, but I happen to think if you've got gobs of liquidity already -- many hundreds of thousands in this case -- then the >>3.0% offer usually easily outranks the 2.5% offer. In addition to being higher yielding, the >>3.0% offer generates more cashflow from as early as age 65, reducing the need to tap your 4.0% interest earning dollars.
The "interest only" withdrawal approach is possible, of course, but interest that stays in SA still earns 4.0% interest. Those are "expensive" dollars to tap, too. Ideally you would reduce and defer SA withdrawals, including interest, in order to let that sweet juicy 4.0% interest work its magic.
I think what I've described is pretty basic cashflow and liquidity management, but just let me know if I haven't explained it well enough.