some of my humble observations

1)for the 10rm monthly maintenance fee of full-flex, it is the same as parking 120(per year)/.0335(blr-2.2) = around 3600rm in it permanently (less if blr rises).

2)for the semi-flex since it will cost around 10rm to 50rm per withdrawal of multiples of 500rm or 1000rm, it would make sense to have some buffer of at least 5k or more (depending on your needs) parked at another savings/current account which acts as the daily/regular money moving account.

3)assuming that the interest earned on this savings account from parking this 5k is minimal (most savings account has pitiful initial tiered interest rates) in the semi-flex scenario, the 10rm monthly maintenance is actually free as the 5k in the semi-flex scenario could have been placed in the full-flex account to cancel off the 10rm, more or less.

4)taking the previous example where the full-flex was blr-2.2 and semi-flex was blr-2.4 the difference of .2% would equate to 200rm/100k loan/year.

so to decide which flex is for you the risk assessment question would be this, in the semi-flex scenario would you be able to control yourself well enough to limit your withdrawal frequencies so that the 10-50rm charged everytime over a year is less than the 200rm/100k loan/year that you would have saved?

my 2cents

If there is a 10% return every year guaranteed and safe, everyone is going to be rich, and i will be the 1st one who will cash out from all my property to invest in it.

Of cause if there is a better return then your loan interest, PLEASE do invest in that. But every investment vehicle have their own risk, please think twice if you can really take up the risk or not. So please invest with the risk that you can affort. If I have 100k in hand, i will not take all 100k for invest. Except the 10% return is guranteed and safe. (but there can get a 10% return guaranteed and safe in this world?)

More over,will you invest your emergency saving in the investment vehicle too? for me, i will not do that as i will need to use it anytime for emergency. But if i'm using flexi loan, i will save my emergency fund and others temporary cash flow in the flexi loan and in the same time enjoy/save a 5% interest guaranteed. And i still can use the money in flexi loan anytime i want.

If we have a good financial planning, we will seperate our money in few fund like emergency fund,investment fund, retirement fund, children education fund, and etc... Thus maybe, about 20%-30% of our money will be goin to investment fund. (for this case will go in the 10% investment vehicle). It is not advise to put 100% of our cash into one fund or investment vehicle.

So, for me
If i have a loan of 100k and 100k in hand, i will still put 100k in the flexi loan.

But if there is some investment vehicle that give better return then my loan interest,and i feel it's safe enough for me, then i will invest maybe 20k in that. And leave the remaining in flexi loan.

And if there's a investment vehicle that give 10% return and it's GUARANTEED and SAFE.
I will put all my money in that and even cash out more from my porperty and invest in it. And wait to be rich.

But in reality it's impossible to find such perfect investment vehicle. Or maybe i haven't found one yet