Same as MMRCA. When the MTA was announced, 2022 (18-27T), Zorawar wasn't part of the requirements. That's also why IL-214 was meant to carry 20T. But now it is. So they are keeping the same weight limits, so as to not be rude to the Americans, just like they did for the F-16 and Gripen E during MMRCA. This also led to people confusing the requirement, without realizing the SEFs were never gonna get shortlisted.
The plan earlier was to buy more IL-476 and upgrade older IL-76, but now they have collapsed that requirement into MTA, so new payload numbers (2025, 18-30T). C-130J will never get shortlisted. Even new C-130s are subject to Trump's antics.
Now, even that 30T limit is a soft requirement. I guess finances will decide whether C-2/A400M or C-390 will be chosen.