To clarify, you won't get assessed 6 times unless the County have agreed that you can go for the double. So, in the example you have given, the referee would need to indicate he would like to apply for double jump and agree that he can do so with the County RDO.
If you are interested, and good enough, there is no reason not to have the conversation with the RDO even at this stage of the season, but they won't know unless you talk with them. There are also a number of people who feel double jumps are bad development moves, so also consider the implications.