A157 With Fail In The Perf At The Top

Hello, I'm from Brazil, and I have this Washington A157 Stamp with this fail in the perf. at the top. Some one has information about this stamp?

The number A157 is a design number. A design number has numerous catalog numbers depending on color, denomination, perforations and also other factors. The Scott Catalog is the most commonly used catalog in the USA for US stamps. Your stamp is either a Scott #554 (11x11 perforations) or a #634 (11x10.5 perforations). The "Washington D. C." overprint is called a precancel.

The fail in the perf is common and usually adds no value to a stamp.

Thank you. I know about the Scott Catalogue, but I thought that the perf fail could increase some value to the stamp. I saw some thing like this a long time ago and the stamp received a good increase of value after the certification about the perf fail, but I don't remember were I saw, anyway I appreciate your help...I keep learning every day....this forum is a great tool for me.

Thank you!!

About 2 years ago I purchased a block of 10 Guatemala stamps that had numerous missing perfs on several stamps. I posted on this forum and the only comments I got were that missing perfs do not increase value but some also told me that missing perfs actually decrease value. I suppose there are exceptions in which value does increase but I don't know how to determine which have an increse in value.

I know of NONE that increase the value....