Technically, yes it does matter as the manufacturer states that ATF+4 is not backwards compatible. So, you can start off with Dex III and switch to ATF+4, but not the other way around.
As mentioned, ATF+4 is a semi-synthetic fluid with anti shudder additives for lockup torque converters. It is a good fluid to use, even in non-lockup applications. We use it in bracket cars with great results.
I don't use or recommend type F fluid.
