Error coins

I realized the other day that one of my 1864 2 cent coins has a rotated reverse. How do you calculate the degrees of the rotation. Is it make the coin worth more? i know alot of old coins have some flaws but no one talks about the increase in value. If you go to Fred Weinburg's website( world reknown error coin dealer), he increases the prices incredibly on alot of errors.Like I said, I'm not too good with degree's, I'd say the rotation is like if you flip it over it's to the right where 3 p.m is on a clock. I'll have to post a pic in the morning.