Does the cost go down again then refunding books?

Every time you have made 10 books of any kind the prices goes up- But been wondering if the same goes the other way around???

By this i mean, does the price go down again if i delete 10 books?

I have 3 geologists, and have 10 manuscripts in each of their skill trees. If i use the 50 % refund ability on all 3, ill lose 15 manuscripts, and in my opinion this should lower the cost on the manuscripts a level.

But does it do this?? Or is the price simple made out from how many manuscripts you have produced, and not how many you own??? (counting used manuscripts in skill tree and in storage)

The price unfortunatly never goes down only up.