Goldwing,
Look at your radio this way. You always have dual rates selected. Just because both rates are at 100% doesn't make any difference. The same goes with the expo. Each rate position also has an associated expo setting. Just go in and make both settings the same to be able to ignore the switch setting.

On a futaba radio, the more negative the expo the less sensitive is the stick movement "from" zero. Always start with a small number. I stared with -40% like someone said when I started and I ripped out the gear of my 1/4 scale Sukhoi twice before I realized that I didn't have enough control/response to land. I reduced the expo to -18% and never had a problem again.