Aarrgghh...we're back to this *sigh*.

For flexiloan, interest is calculated daily and is based on (roughly - I'm not going to show ^365) this:
Interest = BLR * (outstanding loan amount - amount in current acc).

And some bank's flexiloan is overdraft while others are not. Just read your agreement - non-overdraft accounts won't allow you to withdraw more than you have deposited.

Loan with overdraft facilities is more appropriate for business people.