Xianfeng regular script refers to "Xianfeng regular script", which is regular script. I think there seems to be some mistake when you fold it twice and fold it five times. Folding it twice means you can exchange two small coins, and folding it five times means you can exchange five small coins. Actually, it's equivalent to 2 yuan 5 yuan. Dai Shu refers to the handwriting worn by calligraphers in the Qing Dynasty (also known as Dai's handwriting), hence the name.
Baoquan Bureau is actually similar to a manufacturer. I'll give you a picture of Zhang Baoquan wearing a book as a five. Coins like this are rare. The price is also very high.