Okay. Let me close the loop on my end, too! I just updated my MaxIm to the latest version 5.0.18. Quoting from their release notes for v 5.0.16:
"SBIG: Added adjustable speed setting for STX cameras. Removed "fast mode" readout option as obsolete. Fixed incompatibility between AO plug-in and STi."
So my readout mode box is greyed out, too, just like yours. I presume the readout mode now is Normal for all images.
I thought Bob's idea to Fast read pointing images and autofocus images was a good idea, not for my small-format ST7, but especially for those with big cameras like the ST-11000. if you use the SBIG Universal driver, the Fast/Normal selector is out the window. (no pun).
Did I mention earlier that some of my bias images were also taken in Fast readout mode. My master calibration files were hosed up because some bias images and some dark images with both Fast and Normal readout had been mixed together. That was the cause of the "autoflat problems of my own." This is all straightened out now.