Wow!
All we know is that on two occasions Tiger Airways crews descended below MSA on approach.
We do not know what led to that. We do not know if it was two unrelated incidents of crew error or if it is a systemic flaw in training, operation or maintenaince at Tiger Airways.
Some may hold a grouch against Tiger or against LCC airlines or management in general, but the information is not there yet to conclude anything.
CASA has to err on the safe side, and there may be a hint in the steps they have taken, but still nothing conclusive.