Switch to an index fund with a lesser expense ratio?

Hi, I have invested in an index fund with an expense ratio of 0.36. Now I see that there is another index fund, which tracks the same index by a different fund house, and the expense ratio is 0.24. 1) Does it make sense to completely exit from fund A and invest the amount into fund B? There is zero exit load, and I will not be paying any SCTG/LTCG since the returns are negative. 2) Are there any SEBI guidelines regarding how much expense ratio an MF house can set? What's stopping an MF house to lure all investors with a 0.1 expense ratio, and then change it to 0.5 once they have a huge AUM.