Hi Andrew
Yes, that worked perfectly. Thanks so much. I should say that I understand what you were doing before a little better...in theory it should have been working but I think there was a problem with precision as you say. When I removed the level of operations just before adding everything together I got much improved results, though they still missed a couple of lines - probably due to a coincidence between similar cumulative results being rounded to an integer...anyways, the one you prepared did the trick. thanks again
