It is about engine power tolerance on total weight without sacrificing targetted performance parameters. You can load much more than planned but, It will cause to make copter move like a turtle with loosing valuable altitude climb performance.
Z-10 (Empty weight:5580kg) is powered by
2x1000kw turboshaft engine
Tiger HAP (Empty Weight: ~3000kg) is powered by
2x958kw turboshaft engine (
2x1000kw Tiger HAD variant)
Atak (Empty weight: ~2500kg) is powered by
2x1014kw turboshaft engine
Each weapon paylons on Atak can carry max. 300kg (4x300=
1200kg carriage capacity on wings)
4 Mizrak-U missile + Launcher weight: 210kg
MTOW: 5000kg - Empty Weight (2500kg) - Wing load (Fully loaded) 1200kg = 1300kg (Fuel + Other sensors such as MMW radar, ODS detection systems)