Is it possible to change the keypad to the one in the image provided for adding amounts. This way a decimal point can be used with ease. I don't like the calculator option because the buttons are too small and there is no paste option. The native android buttons are better to use.
Sure thing -- you can switch to the Android default keyboard in the Settings of the app. Tap on the overflow menu (the three dots in the upper-right), then on Settings, then scroll down to the option labelled "Calculator" and uncheck the box. After doing this, the next time you add an Amount you should see the number input screen you added the screenshot of.