Yes it is correct that you require the RF transmitter to use the full features of Green RF mode BUT you do NOT need it for Red Mode which has all the same features, including the anti-jam, the reverse button and upto 42 balls per second feeding, except the link to the marker.
Some are seeing the Transmitter upgrade as a later option and this was the reason for seperating the Transmitter because they do not want to mess with their circuit boards.
To answer Marks point: The RRP of the RF Transmitter is £25. Some are offering free fitting but that may be for a limited time. Check with your local dealer.