There are a few ways to get a point curve for the second aileron channel.

First, don't select a model type of 2 ailerons. Just 1 aileron. Then enter your own channel selections in the Function section of the Model menu. Make two adjacent channels "Aileron". DO NOT select Aileron2 or Aileron3, etc. Set both channels to the same control and trim. You can then adjust the second channel's endpoints, centering, and curve points as needed. The problem with this is that you will have to set up dual rates for each channel involved. Just setting a rate for the aileron isn't enough. You'll need to set the rates for each channel you use. However, with 8 conditions available, you can have up to 8 rates for all channels.

You can also use a pmix. Select the 1 aileron wing type and make two adjacent channels for the ailerons. Select one as "Aileron" and the other as Auxiliary 1 (or any other number). Select the control and trim for the Aileron channel. Use a Pmix to mix the second channel to the other channels. In our example, "Aileron" is master and Auxiliary 1 is slave. Set up the mix points as you desire to get the second channel to follow the first channel.

In earlier software versions, you could just select a 2-aileron wing and you'd have AFR points for both channels. Futaba, though, eliminated this in later versions because people would find that setting a lower percentage of the second channel actually reduced it by that percentage of the first channel, and not of the original total. So if you set the second channel to 90% at one point, it would be 90
% of the rate of the first channel, and not 90% of the total throw of the second channel. It made adjustments confusing.