My DVLA car tax refund; I'm I being diddled?

[Sa Calobra]

I taxed my car in mid Jan 2017 and cancelled it a week ago.

The annual tax paid was £150 and my refund is £54.16.

Is this right?

I calculate that I'm owed 5 months refund as Jan and July count as whole months. So it's 62.50. curious as to how they calculate refunds?? Am I missing something?

[Sa Calobra]

Yes the car was bought in Jan, tax cancelled last week.