Doing that will make Karnataka to have extra rake.
But there is one solution
One option is speed up Island express and make Island and Karnataka to have RSA with each other so Island arriving SBC at morning 07:30 AM would leave at 19:00 at night and KA arriving at 10:30 AM (speed up) would leave SBC as Island at 21:30...
more... PM towards CAPE
Also, they should break 12633 and 16525 RSA and give 12633 and 12657 to have RSA with each other and maintain in TBM , with 12634 arriving MS at 07:00 AM lets say in the morning should leave as SBC mail at night 21:45 PM from TBM and SBC MAS mail that arrive TBM at 04:30 AM should leave as CAPE SF at 17:00 from MS. But SR need two rakes to do that and SR is not kind enough to accept any of its old trains back. (Yes SBC mail was Madras own train that was given up by SR and adapted by SWR). SR is lazy.