"Higher Capacity Goo Tanks weapon upgrade" for scientist in pz 1

[342052082]

Hi, everyone 

I am doing pretty good with the relatively old game plants and zombies garden warfare 1, but I am confused about one weapon upgrade for scientist. 

I used nearly 700,000 coins in the game to unlock this weapon upgrade and finally I found the upgrade didn't work in game. The maximum ammo capacity of the scientist is only 5 and for the Higher Capacity Goo Tanks upgrade, it shows this:

Goo tank capacity increased resulting in more ammo capacity.

So I am wondering is this upgrade really working? because for the scientist, one ammo increase is REALLY and RIDICULOUSly helps the play in this game. 

Thanks. 

jiaxin