After years of supporting using "true RF frequency" for PSK31, I have given up, because too many people still get confused trying to calculate the "true RF frequency". So for our net, I now say, "Set your transceiver dial frequency to 144.144, USB, and net control will be at 1500 Hz tone frequency, unless the frequency is already occupied, and then net control will be on the nearest higher clear tone frequency".
If someone prefers to use a different "sweet spot", he will just have to make the necessary calculations. 73, Skip KH6TY
