Here’s the issue. Limiting the mech weight to 1,000 kg doesn’t make any sense at all.
What I think should happen is that the mech’s legs have a weight capacity, because, of course, legs are what keeps the bloody thing standing. Mech legs should have different weight capacities, though some might overlap. The better, more sturdy, and legs that have the best springs should have the highest weight capacity, and vice versa.