OK Jim,
So, just to double check --- in your Settings for "Configure MIDI Connections", do you have a check mark in both boxes for "MIDI Input Devices" and also for "MIDI Output Devices" ? They both must be selected within the check box. I guess it's possible that they could have accidentally been de-selected?
Another possibility --- for your MIDI Device, is it selected for "Genos, PSR-SX600/700/900" ?
If they are all set correctly, can you try creating a new Song in Mobile Sheets? Setup a test registration on your keyboard, and then create a Song with a .pdf, and
verify that you go to the MIDI page, and click on the "chain link" Icon. When you do that you should see 2 Batch commands appear on the screen, and click "OK".
The commands will say "Send on Load" for one, and "Load on Receive" for the other. That is by default how the 2 directions are enabled.
Hope that might help, Jerry