What is the percentile cutoff for IBS Hyderabad with respect to the IBSAT percentile?

Firstly, ISB Hyderabad has no cutoff whatsoever. In fact, the marks of ISBAT and individual subjects are not revealed ever. The eligible candidates directly receive a call inviting them to the GD-PI process. So attempting the test with full confidence and preparation is more than enough to get the call. Since there is no negative marking you can attempt as many questions as possible.

The main struggle starts post-ISBAT if you get selected for GD-PI. From around 20000 shortlisted candidates only 1200 are selected for the main campus. So instead of ISBAT, your main focus should be on preparing for the GD-PI round. Anyone with decent aptitude skills can get shortlisted but only a few who have an extraordinary profile and stand out from the crowd can get selected during the GD-PI process.