1.2ml + 0.3ml + 0.3ml = 1.8ml in 5ml is 36% flavor.
Since I have no idea what flavoring you are using, and thus have no clue if this is too much, I'm going to go out on a limb and say, "It's probably too much flavoring that is causing the light flavor."
Take a look under my picture there to the left. Click that number "3" just next to "Blog Entries:". Then click on the one on Flavoring Levels.
I know I like strong flavor, so it took me awhile to figure out that too much is just about the same as too little. "just about", because I include in that blog how to tell the difference between too much and too little even though they may taste much the same.