The Lynx AH9 when introduced had a greater MAUM than its predecesor the Lynx AH7.
The rationale explained at the time was the Lynx AH7 skided undercarriage was the limiting factor on the aircraft AUM, the rest of the airframe was capable of greater AUM.
The introduction of the Lynx AH9 incorporated significant reinforcement of the airframe to take the wheeled undercarriage and therefore the airframe could carry the extra AUM.
Ironically a MK7 with no TOW equipment or roof sight has a greater payload than the MK9 when all the reinforcing of the airframe is taken into account in the basic weight.
HEDP