I know this isn't my thread, but I've got a quick question about the CYA test too...

When I do my testing I generally sit at my kitchen table. I do my CYA test standing at the window (my kitchen window faces East, so I get morning sun). This morning my results standing at the window were 50. Just for kicks I stepped outside on my porch in the direct sunlight to see what I got there. Out on the porch I was able to add more of the testing mixture before the last hint of the dot completely disappeared and got a reading of 40. So, which is the most accurate reading?