Empire Porcelain " Rose" Two Backstamps - 24 KT SPECIAL PAULA

The plates have two backstamps which is confusing. The gold and yellow crest backstamp was made in the 1930's. The other stamps with the flower and leaves have a date which according to the Empire Porcelain marks by Staffordshire say they wer made in the 1950's. But that is not all. The one plate has 666 on it which would indicate it was made in the 1960's. If it was it should have a different flower which was the PEONY for the 1960's done in color. This is confusing. Any one who could shed some light on why the plates were stamped this way, please do. The pattern is called ROSE. They are a dinner plate size of 10" . They have embossing on both side of the flowers and are very pretty.