Not all glass marked as COE90 behaves in the same way. Even in a pot melt the glass needs to be compatible at the start. Not all so called CoE90 glass is compatible.
Still, at pot melt temperatures there will be little difference in the flow characteristics of what ever glass you use. Just make sure it is compatible glass, or you will have breaks at or soon after the firing.
Stephen Richard
blogs at: http://www.verrier-glass.blogspot.com/ and http://www.glasstips.blogspot.com/