ChangeActorPool: SParam1?

[jastaV]

ChangeActorPool $gmaOptionMil|MaxUse|1|ResetFreq|0|ImageID|None.png|Title|opt_title_FRA06_2|MsgString|opt_desc_FRA06_2|ToolString|opt_hint_FRA06_2|SubType|FRA_MilitaryOption2|[color="DeepSkyBlue"]SParam1|FRA[/color]

ChangeActorPool $gmaOptionMil|MaxUse|1|ResetFreq|0|ImageID|None.png|Title|opt_title_COA06_1|MsgString|opt_desc_COA06_1|ToolString|opt_hint_COA06_1|SubType|COA_MilitaryOption1|[color="deepskyblue"]SParam1|PRU[/color]

ChangeActorPool $gmaOptionMil|MaxUse|1|ResetFreq|0|ImageID|None.png|Title|opt_title_COA_ACTI|MsgString|opt_desc_COA_ACTI|ToolString|opt_hint_COA_ACTI|SubType|COA_MilitaryOption_ACTI|[color="deepskyblue"]SParam1|RUS[/color]

I enlisted here 3 examples of ChangeActorPool strings from NCP 1815 default scenario.

I'm confused as regard the meaning of the SParam1.......
Why to use different Tags for Coalition side rather than COA?
Expecially cannot understand the use of the [color="deepskyblue"]SParam1|RUS[/color]
RUS has nothing to deal with 1815 scenario beeing it a FRA vs. ENG & PRU match!..... None the less the options works properly!

[Pocus]

These params are used to get the signature to be used when signing the option, that's all. RUS tag is an error, replace by PRU if you prefer, this won't change much as all the COA side gets the same signature