Scoreboard parameters not working

I was making a command block contraption which had some custom cultivation. Basically, you dropped the seeds, than it would spawn an invisible armor stand and make a "plant". I created a scoreboard objective called "PlantTime" and every tick 1 would be added to the armor stand's PlantTime score until it reached 8400 ticks. Initially, I didn't put "score_PlantTime=8400", and it was working. But when I added this parameter, it stopped working. I checked many times and I didn't misspell anything. Here is the command:

"/scoreboard players add @e[tag=TomatoPlant,score_PlantTime=8400] PlantTime 1"

It was on a repeating command block, Always Active. Also, "TomatoPlant" was the armor stand's tag. I checked with another scoreboard and using only armor stands (without tags or anything else) in another world and it didn't work aswell. score_Something_min works, however score_Something doesn't.
I really hope this can be resolved.
Best Wishes, Igor.