This command associates a single power supply with each letter. You select a group of letters to limit this to those letters, otherwise all LED objects are processed. If a group of letters was selected when starting PowerFlow, that group is used.

The "Auto Select PS" part of this feature means that it also automatically selects the appropriate power supply for each letter. Or to put it another way, the power supply is not limited to just the one selected.

In this example, these two letters were a Group, and with this feature, the first letter gets a 20W power supply, and the second letter gets a 40W power supply.