Hi Peter,
Thank you for giving your feedback, It will be provided to the team that looks after the documentation.
In general - free run settings are totally up to the user. You may want to enable autobuffering mode or not, and similarly - you may want either HDMI-COMP or HDMI-GR which will result in free-runing to respectively component or graphic mode. This flexibility is given to ensure that your backend is satisifed with free-run resolution when no input is applied or lock is lost.
WHen it comes to 720x576 - this standard is in fairness 13.5MHz of pixel frequency. It is pixel-repeated in transmission to ensure that frequency is above min. 25MHz frequency that HDMI spec allows. You may want force pixel repetition to get 27Mhz if this is required. But 27MHz is not a native frequency of this video standard.
Hope this helps,
Rgds,
vito