So here it is:

Each of those is a slice of a brain, #1 is towards the front, # 36 is most towards the back. What I want to do is compare the area of the left side with the area of the right side for each slice and see how this changes going from front to back. Let's ignore the right side for now.

If I use the quick selection tool to select each of the left sides (#6 to #36) and then "record measurements" (under analyze), I get this ordering:

"Document" "Scale Units" "Count" "Area"

"280.psd" "cm" "31" "14.302058"

"280.psd" "cm" "0.217312"

"280.psd" "cm" "0.244420"

"280.psd" "cm" "0.262937"

"280.psd" "cm" "0.270576"

"280.psd" "cm" "0.308789"

"280.psd" "cm" "0.337050"

"280.psd" "cm" "0.352047"

"280.psd" "cm" "0.358225"

"280.psd" "cm" "0.376706"

"280.psd" "cm" "0.401809"

"280.psd" "cm" "0.412669"

"280.psd" "cm" "0.422004"

"280.psd" "cm" "0.424898"

"280.psd" "cm" "0.461796"

"280.psd" "cm" "0.472783"

"280.psd" "cm" "0.462867"

"280.psd" "cm" "0.494974"

"280.psd" "cm" "0.502196"

"280.psd" "cm" "0.514262"

"280.psd" "cm" "0.536235"

"280.psd" "cm" "0.545036"

"280.psd" "cm" "0.561738"

"280.psd" "cm" "0.562155"

"280.psd" "cm" "0.573813"

"280.psd" "cm" "0.646003"

"280.psd" "cm" "0.663023"

"280.psd" "cm" "0.623948"

"280.psd" "cm" "0.533713"

"280.psd" "cm" "0.565140"

"280.psd" "cm" "0.608116"

"280.psd" "cm" "0.584818"

If I hit "record measurements" after selecting each left side (going from top row left to right, then second row left to right, then third row left to right)... It orders them this way:

"280.psd" "cm" "1" "0.217312"

"280.psd" "cm" "1" "0.244420"

"280.psd" "cm" "1" "0.262937"

"280.psd" "cm" "1" "0.270576"

"280.psd" "cm" "1" "0.308789"

"280.psd" "cm" "1" "0.337050"

"280.psd" "cm" "1" "0.352047"

"280.psd" "cm" "1" "0.358225"

"280.psd" "cm" "1" "0.376706"

"280.psd" "cm" "1" "0.401809"

"280.psd" "cm" "1" "0.412669"

"280.psd" "cm" "1" "0.422004"

"280.psd" "cm" "1" "0.424898"

"280.psd" "cm" "1" "0.461796"

"280.psd" "cm" "1" "0.472783"

"280.psd" "cm" "1" "0.462867"

"280.psd" "cm" "1" "0.494974"

"280.psd" "cm" "1" "0.502196"

"280.psd" "cm" "1" "0.514262"

"280.psd" "cm" "1" "0.536235"

"280.psd" "cm" "1" "0.545036"

"280.psd" "cm" "1" "0.533713"

"280.psd" "cm" "1" "0.561738"

"280.psd" "cm" "1" "0.562155"

"280.psd" "cm" "1" "0.565140"

"280.psd" "cm" "1" "0.573813"

"280.psd" "cm" "1" "0.608116"

"280.psd" "cm" "1" "0.584818"

"280.psd" "cm" "1" "0.646003"

"280.psd" "cm" "1" "0.663023"

"280.psd" "cm" "1" "0.623948"

The ordering is the same until it gets to the last row (starting at #27). The last 10 measurements are ordered in some strange way. The last of the common ordering is # 26:

"280.psd" "cm" "1" "0.545036"

It is much faster to select all of the left hemisphere then hit record than to hit record after selecting each. The second way of ordering is what I want to get by using the first method. I can't figure out why the last row is getting put out of order. I can send the file if interested.