Why DP charges have to be 13 Rs flat and not a percentage?

Why DP charges have to be 13 Rs flat and not a percentage?
This is huge advantage for FEW institutions and big players who don’t need these benefits. But, huge disadvantage for MILLIONs of we retail traders/investors.

How do we get this changed to a percentage ? I can see the big players fuming because they have been enjoying this.