I see that we are adding / subtracting a CTQ_BER_COMP depending on tab. It appears that this tab offset may have switched and I would like to investigate possible sources for this change.
In the attachment, you can see that for D6Z, and early E6Z TSR we show the UP tab with lower residual in the CTQ_BER vs CTQ_WRT_WDTH. Later, the E/F6Z TSR LM09E6ZP script date 06/09/2016 seems to show no tab offset. More recently, we have moved to SCRIPT_DATE 06/28/2016 and the tab offset is reversed (up tab with higher residual).