Is it likely for a pension plan to lose 13% in interest over an 8 month period?

I left a company where I had accumulated a small pension. I am having a family emergency so I have to cash it out. Yes, I am able to do that. And yes, I understand that it is a bad idea, but I have to. When I left the company I was quoted a lump sum amount, but since the materials are 8 months outdated they had to re-calculate the sum. I assumed that it would either increase being that it has had more opportunity to mature or stay the same. The new lump sum is 13% less than the original. Is that possible? Should I be investigating this further before I take the money and run?