My son has had this problem a few times, the week he was first diagnosed the diabetes nurse said to him, 'We usually put builders and the likes of your dad on 4 but you'll only need 2'. She then tried to prick his finger on 2, then on 2 1/2, then on 3, then on 3 1/2 then on 4 and finally got blood at 5! She was very apologetic.
After a few weeks he did go down to 2 1/2, but every so often we have to dial the lancet machine up.
I put it down to his dad being Scottish and me being from Yorkshire, a recipe for stinginess if ever I heard it!
Kind regards
Pud x