HP Bonus (Unit Statistics)
Determines the HP bonus of the selected unit. This bonus is added to the base hitpoint value (determined by the unit's experience level) of any units of the selected type. This field would alllow you to give tanks more hitpoints than infantry, for example. Accepted values are between -20 and 20.
NOTE: While you can assign a negative hitpoint bonus to a unit, the unit’s total number of HP will never drop below 1. Therefore, setting a unit HP bonus to -20 when its base HP is 5 will still result in a unit with 1 HP.