Center section end play measurement per CK perf vs ATSG

[PaulRV6]

I have a few questions regarding this measurement. In CK manual it calls it "center section end play" and ATSG manual refers to "front unit end play". Are these one in the same?
CK says to lift up on the direct housing and measure how much it moves up, that is the clearance. This should be btw .006-.008. Using a dial caliper which is not very consistent readings but I was getting .019"
ATSG says to pull up on the forward clutch housing and measure how much the shaft moves up. It says to be btw .022-.051". I use a dial indicator on the shaft end and when I pull up it consistently reads .022".
Are these two different checks? I currently have a yellow #9 washer installed.
My previous rebuild I used the #9 washer and I was at .026" end play using the ATSG procedure.
Please help me understand these two procedures and what the differences are?
I may or may not need to find a thicker washer depending on what you folks tell me. Thanks
This is on my 2004R.

paul

 

[INEEDAGN]

ATSG is not performance oriented. In high HP applications, the tighter end play helps the thrust washers live longer. Less room for the hard parts to "get a run for it" as the thrust surfaces load/unload when we drive like maniacs. Can't comment on which measurement is more accurate. It will run either way, but tighter is better.