There has been work since this iteration and what you ask for is a 'bug' that needs worked out more than less. There is a plugin that breaks the hard limits of CVARs made years ago. That might need used to unlock the clamped values like the old days of beta.
You might want to claritfy please because if the c4 explodes instantly each round start who will remain on server if all it does is explode the T team each round start?
What he ment was: when the bomb explodes the next round starts INSTANTLY - turn down the delay between round end event and new round event.