If I have $100,000 of credit, with $3000 spread across 8 different cards, that gives me a debt to credit ratio of 3000/100000 = 3%. If I start canceling cards, and consolidating, so that I now have 2 cards, and only $10,000 of total credit, my debt-to-credit ratio jacks up to a whopping 30%. It would adversely affect credit in the same manner if I did not cancel cards and instead spent $27,000 in a short period of time.

Calvin