As Gegogi mentioned it depends on the product you purchase as some are different.
Sprays to make a ML have nothing to do with dosage of pheromones unless your making your own composite and need the conversion for that.
No the formula is exactly the same but the spray nozzle is smaller. You get 83.74% of the spray from a to-go bottle. Without doing the actual math cause I am lazy thats about 13.8 mcg per spray of pheromone in the example used above.
Are you trying to figure out the pheromone content in each spray or the total volume of ML to carrier ratio
To figure out the pheromone content per spray it would be …
Total pheromone content in bottle 3000 mcg
Divided by the number of sprays in bottle (200) = 15mcg per spray of pheromone.
I can covert when mixing how many total ML to use to get the desired MCG per spray.
milligram/liter = microgram/milliliter
there are 1000 mcg in 1 ML so you would use this as a guide in mixing depending on the size bottle you are using to composite in.
Yes I do believe your correct, math is not my strong suit. 6.5 sprays in the above example you posted would be would just be slightly under 1ML. 
Tisha