So forming persia as Persian is impossible, and Persia is always Turko Persian colours? You are making persia, therefore it should be Persian Blue, Persians didn’t used turkic colours when Seljuks arrived. They still used Persian Blue.
Oh, seriously?
It might be shocking, but France doesn't have the exact Paris blue, Bohemia is brown instead of bright red, England has some lighted version of its traditional shining red.... the Abbasids are dark green instead of Black, Fatimid Egypt also doesn't have the exact shade of green they used, even the Byzantines/Romans/ERE have slightly different shade of purple, the same can be said about Norway, Ireland, Sweden, Rus, every single entity on the map. Why? because...
... you might say because they are "impossible to form as French/Bohemian/English/Arab/Greek/Norwegean, Irish, Swedish etc."? Oh come on!
I haven't seen a single person of these amazing nations complaining that the color of their kingdom or empire isn't THE EXACT SHADE IT SHOULD HAVE. Now, yes, Persia is green in game, which isn't right. So here comes a guy, who shows
a mod, which improves it and makes Persia blue. And what happens? You demand it having the exact shade you want. That's just awesome!
You know, mate. If you look around, you might realize that we are talking about a video game. The colours, just like everything else in this game are there primarily to have some function to faciliate pleasing and fun gameplay. Not to be 10000% accurate. While the exact shade of Persian blue (btw there are 3 possible variations of Persian blue, as you know) is beautiful and everything, for the gameplay purpouse of it covering huge sections of map it is way too rich, so some sort of lighter shade has to be taken.
And the fact that this lighter shade can represent both traditional Persian colour and the greatest medieval empire to be present in Persia is just a consensual way of looking at things. If you are a consensual person.