The following snippet provides the implementation for pet power item focus. The focus has been setup to provide a prescribed percentage increase, which should scale with level nicely.
Code has been pre-tested locally for bugs.
{Zone\spdat.h}
find  (line ~241)
	Code:
	#define SE_PetPowerIncrease			167	//not implemented, base % increase of pet stuff
 and replace comment
	Code:
	#define SE_PetPowerIncrease			167	//percentage boost to pet HP, min/max damage, min/max HP
 {Zone\client.h}
find (line ~88)
	Code:
	typedef enum {	//focus types
	focusSpellHaste = 1,
	focusSpellDuration,
	focusRange,
	focusReagentCost,
	focusManaCost,
	focusImprovedHeal,
	focusImprovedDamage,
	focusImprovedDOT,		//i dont know about this...
	focusImprovedCritical,
	focusImprovedUndeadDamage
 and add a new item to the enum
{Zone\spell_effects.cpp}
find (line ~3269)
	Code:
	case SE_ReduceManaCost:
			if (type == focusManaCost && focus_spell.base[i] > value)
			{
				value = focus_spell.base[i];
			}
			break;
 and add:
	Code:
	case SE_PetPowerIncrease:
			if (type == focusPetPower && focus_spell.base[i] > value)
			{
				value = focus_spell.base[i];
			}
			break;
 {Zone\pets.cpp}
in void MakePet, around line 190, find the following:
	Code:
	memcpy(npc_type, base, sizeof(NPCType));
 and add below:
	Code:
		// focus effects only apply for client casters
	// the pet is either focused or not, the value on the item is irrelevant
	if (this->IsClient() && CastToClient()->GetFocusEffect(focusPetPower, spell_id) > 0)
	{
		npc_type->max_hp *= 1.20;
		npc_type->cur_hp = npc_type->max_hp;
		npc_type->AC *= 1.20;
		npc_type->level += 1;
		npc_type->min_dmg *= 1.10;
		npc_type->max_dmg *= 1.10;
	}