Paddy the accountant

Paddy wanted to be an accountant, so he went for an aptitude test:
Tester: “If I give you two rabbits, and two rabbits, and another two rabbits, how many rabbits have you got?”
Paddy: “Seven.”
Tester: “No, listen carefully again. If I give you two rabbits, and two rabbits, and another two rabbits, how many rabbits have you got?”
Paddy: “Seven.”
Tester: “Let’s try this another way. If I give you two bottles of beer, and two bottles of beer, and another two bottles of beer, how many bottles of beer have you got?”
Paddy: “Six.”
Tester: “Good! Now, if I give you two rabbits, and two rabbits, and another two rabbits, how many rabbits have you got?”
Paddy: “Seven.”
Tester: “How on Earth do you work out that three lots of two rabbits is seven?”
Paddy: “I’ve already got one rabbit at home now!”