Mine is similar except I garage and anneal for an hour both at 940, ramp down 50 per hour to 870 where they sit for half an hour, then ramp down again to 680 for half an hour (my Jim Kervin book says the 104 stress point is at 680, this forum says 870, so I do both) then down to 400 and off.
It seems to be like Lauscha, some people can use it fine and mix it with other glass and never have a problem and some people do. I think the CIM line has some of the most beautiful colours anywhere and I wish I was one of those people who could work it without issue, but sadly that's not the case.