Hello!
I hate to be the one to point this out, but this letter was NOT written by Cindy Williams of Laverne and Shirley, rather it was written by Cindy Williams of Massachusetts Institute of Technology .
Please see http://www.snopes.com/military/gipay.htm for further clarification.
We all have to be so careful with the internet, it is really easy to read something and automatically assume it is true just because it is written somewhere on the internet. I read an interview with Cindy Williams of Laverne and Shirley, and she is apparantly very upset that people are attributing this to her.