And you are getting an effective ISO of 80? Interesting. My Fuji X-ray is giving me an effective ISO of 200 (HC-110 1:50, 5 mins). Is this just due to the developer, or is it less sensitive in general? Do you know what it is sensitive to? I believe mine is green.
I was told to start at 80 ISO, and it has worked for me. I think it is also there reason for the longer development times that I need. My film is the green type.